UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


LABORATORY  MANUAL 


CONTAINING 


DIRECTIONS  FOR  A  COURSE  OF  EXPERIMENTS 
IN  ORGANIC  CHEMISTRY 


SYSTEMATICALLY   ARRANGED   TO   ACCOMPANY 

REMSEN'S  ORGANIC  CHEMISTRY 
REVISION  OF  1922 


W.  R.  ORNDORFF,  A.B.,  PH.D. 

PROFESSOR  OF  ORGANIC  CHEMISTRY  IN   CORNELL  UNIVERSITY 


D.   C.    HEATH    &    CO.,   PUBLISHERS 

BOSTON    NEW  YORK    CHICAGO 


COPYRIGHT,  1893,  1913 

AND   1922  BY 

W.  R,  ORNDORFF 
sai 


Printed  in  U.  S.  A. 


O74 

• 

INTRODUCTION 

The  student  is  expected  to  be  familiar  with  the  General 
Part  of  Gatterman's  Practical  Methods  of  Organic  Chem- 
istry, translated  by  Schober  and  Babasinian,  3d  American 
Edition,  pages  1  to  77.  Descriptions  of  the  methods 
used  in  the  Laboratory  of  Organic  Chemistry  will  be 
found  in  this  part  of  the  book. 

Before  beginning  any  experiment  the  student  is  ex- 
pected to  read  carefully  the  directions  given  in  the  Lab- 
oratory Manual  for  that  experiment  and  to  be  sure  that 
he  understands  them.  If  in  doubt  about  any  point  he 
should  consult  the  instructor  or  the  assistant  before  be- 
ginning the  experiment.  He  is  urged  to  read  ahead  of 
the  experiment  he  is  doing,  when  opportunity  presents 
itself,  and  he  will  find  that  it  is  frequently  possible  to  be 
carrying  on  two  or  more  experiments  at  the  same  time. 
It  is  necessary  to  use  every  minute  in  the  laboratory  to 
advantage  in  order  to  finish  the  required  work  in  the 
allotted  time. 

When  the  apparatus  required  for  the  experiment  has 
been  set  up  according  to  the  directions  given  in  the 
manual  the  student  requests  the  assistant  in  charge  of 
his  section  in  the  laboratory  to  inspect  it.  If  the  ap- 
paratus is  satisfactory  the  student  may  begin  the  work. 
If  it  is  not  satisfactory  the  assistant  will  indicate  what 
changes  are  necessary.  The  experiment  is  then  per- 
formed by  the  student  and  the  results  are  inspected  by 
the  assistant.  Thus  each  experiment  is  checked  at  the 
beginning  and  at  the  end  by  the  assistant,  who  also 
watches  the  student  while  the  experiment  is  in  progress. 
If  the  method  of  procedure  is  not  correct  or  could  be 
bettered,  the  student  is  at  once  informed  of  it.  The 
directions  given  in  the  laboratory  manual  must  be  fol- 


lowed  very  carefully  or  the  experiment  will  fail  and  will 
have  to  be  repeated.  It  is  never  necessary  to  repeat  an 
experiment  if  the  directions  in  the  manual  and  the  ad- 
vice of  the  assistant  are  followed  carefully. 

Blank  pages  are  provided  in  the  manual  so  that  any 
observations  or  data  may  be  recorded  immediately. 
The  experiments  should  be  written  up  as  soon  as  pos- 
sible after  the  experimental  work  is  finished  and  in  ac- 
cordance with  the  following  outline: 

1.  All  the  reactions  involved  in  the  preparation  of  the 
compounds,  including  all  intermediate  steps. 

2.  Observations    and    answers    to    questions.     Some- 
times  questions   are   indicated   by   putting   an   interro- 
gation mark  in  parentheses  after  a  statement. 

3.  The    percentage    yield.     The    percentage    yield    of 
each  compound   prepared  is  determined  by  comparing 
the  weight  of  the  compound  found  with  the  theoretical 
amount  calculated  from  the  equation. 

For  example,  in  Experiment  49,  suppose  that  20  grams  of  aniline 
were  obtained  from  the  40  grams  of  nitrobenzene  used.  The  theo- 
retical amount  according  to  the  equation: 

C6H5NO2  +3H2  =  C6H8NH2  +  2H2O 

123  93 

is  calculated  from  the  proportion: 

123     :    93     ::    40     :    x 
x  =  30 . 24  grams  of  aniline. 

As  20  grams  of  aniline  were  obtained  the  percentage  yield  would  be: 

nr\ 

^4X  100  =  66.1% 

From  time  to  time  the  student  will  be  called  into  the 
office  of  the  instructor  for  an  informal  oral  quiz  cover- 
ing the  work  finished.  Questions  will  be  asked  on  the 
laboratory  procedure  and  on  the  theoretical  part  of  the 
work.  An  attempt  is  made  in  these  quizzes  to  make 
clear  parts  of  the  theoretical  work  that  the  student  has 
confused  or  misunderstood  and  to  find  out  if  he  knows 
what  he  has  been  doing. 


Samples  of  the  compounds  made  are  saved  and  are 
shown  to  the  instructor  at  the  quizzes.  These  should 
be  put  in  small  homeopathic  vials,  labeled  with  the  name 
of  the  substance,  boiling  point  or  melting  point,  date  of 
preparation  and  name  of  the  student. 

In  working  in  the  laboratory  the  student  must  keep 
the  glass  ware  and  apparatus  clean.  No  dirty  apparatus 
should  be  put  away  in  the  desk.  Neatness  and  order  are 
essential  for  good  work  in  the  laboratory  and  will  be 
insisted  upon.  Great  care  should  be  exercised  in  work- 
ing in  the  Laboratory  of  Organic  Chemistry.  The  stu- 
dent should  remember  that  many  of  the  organic  com- 
pounds with  which  he  works  take  fire  readily  and  some 
of  them  are  poisonous.  There  is  no  danger  provided 
that  ordinary  care  is  taken  and  the  directions  are  fol- 
lowed closely.  In  any  work  where  especial  precautions 
are  necessary  the  attention  of  the  student  is  called  to  it 
in  the  directions  for  the  experiment. 

Gas-tight  goggles  are  provided  for  every  student  and 
they  must  be  worn  whenever  there  is  any  danger  of 
injury  to  the  eyes. 


CONTENTS 

EXPERIMENT  PAGE 

1.  FRACTIONAL  DISTILLATION 1 

2.  FRACTIONAL  DISTILLATION  WITH  A  HEMPEL 

DISTILLING  TUBE 6 

3.  DETERMINATION  OF  THE  MELTING  POINT       .  8 

4.  DETERMINATION  OF  THE  BOILING  POINT  OF  A 

SMALL  AMOUNT  OF  LIQUID 10 

5.  METHANE 12 

6.  CHLOROFORM 16 

7.  IODOFORM 20 

8.  ETHYL  BROMIDE 22 

9.  FERMENTATION  OF  GLUCOSE 24 

10.  ABSOLUTE  ALCOHOL 28 

11.  CALCIUM  ETHYL  SULPHATE 30 

12.  ETHER 32 

13.  ALDEHYDE 36 

14.  ALDEHYDE  AMMONIA 38 

15.  METALDEHYDE  AND  PARALDEHYDE       ...  38 

16.  DETECTION  OF  ALDEHYDE 40 

17.  FORMIC  ACID .  42 

18.  ACETIC  ACID 46 

19.  SEPARATION  OF  IRON  FROM  MANGANESE,  ZINC, 

ETC 48 

20.  ACETYL  CHLORIDE 50 

21.  ACETIC  ANHYDRIDE 52 

22.  ETHYL  ACETATE 54 

23.  SAPONIFICATION 56 

24.  POTASSIUM  CYANIDE 58 

25.  POTASSIUM  FERRICYANIDE     ......  60 

26.  POTASSIUM  CYANATE        62 

27.  POTASSIUM  THIOCYANATE 64 

vi 


EXPERIMENT  PAGE 

28.  AMMONIUM  THIOCYANATE 66 

29.  ALDEHYDE 66 

30.  PALMITIC  ACID,  STEARIC  ACID,  AND  GLYCEROL  68 

31.  OXALIC  ACID 72 

32.  BASIC  FERRIC  SUCCINATE 74 

33.  FEHLING'S  SOLUTION 74 

34.  PHENYLGLUCOSAZONE        76 

35.  HYDROLYSIS  OF  SUCROSE 78 

36.  CELLULOSE 78 

37.  CELLULOSE  ACETATE        80 

38.  SCHWEIZER'S  REAGENT     .......  82 

39.  STARCH 84 

40.  HYDROLYSIS  OF  STARCH 84 

41.  ETHYL  FORMATE,  ETHYL  OXALATE  AND  OX- 

AMIDE       ;     . 86 

42.  UREA 88 

43.  ETHYLENE  AND  ETHYLENE  BROMIDE    ...  90 

44.  ALLYL  ALCOHOL  AND  ACROLEIN       .      .     .     .  92 

45.  ACETYLENE        . 94 

46.  BENZENE 96 

47.  NITROBENZENE 98 

48.  DlNITROBENZENE 100 

49.  ANILINE 102 

50.  PHENYL  ISOCYANIDE 104 

51.  W-NlTROANILINE 106 

52.  ACETANILIDE 108 

53.  BENZENE  DIAZONIUM  CHLORIDE       108 

54.  lODOBENZENE,  lODOBENZENE  DlCHLORIDE,  AND 

lODOSOBENZENE 112 

55.  BENZENE  SULPHONIC  ACID 114 

56.  BENZENE  SULPHONYL  CHLORIDE  AND  BENZENE 

SULPHONAMIDE 116 

57.  PHENYL  CYANIDE  (BENZONITRIL)  AND  BENZOIC 

ACID 118 

58.  PHENOL  FROM  SODIUM  BENZENE  SULPHONATE  120 

59.  PHENOL  FROM  ANILINE 122 

60.  ORTHO-  AND  PARANITROPHENOLS  124 


EXPERIMENT  PAGE 

61.  PICRIC  ACID 126 

62.  BENZYL  ALCOHOL  AND  BENZOIC  ACID  FROM 

BENZALDEHYDE        128 

63.  BENZOIC  ACID 130 

64.  ETHYL  BENZOATE 132 

65.  GRIGNARD'S  REACTION,  BENZHYDROL     .      .      .  134 

66.  PHTHALIC  ANHYDRIDE  AND  PHTHALIC  ACID    .  138 

67.  SALICYLIC  ACID      .     .     . 140 

68.  ACETYL  SALICYLIC  ACID 142 

69.  SALICYLIC  AND  PARAHYDROXY  BENZOIC  ALDE- 

HYDES     ....,." 144 

70.  PARAROSANILINE 148 

71.  FLUORESCEIN 150 

72.  EOSIN  AND  SOLUBLE  EOSIN 152 

73.  CRYSTAL  VIOLET 154 

74.  INDIGOCARMINE      .      .      .     ...     .     .     .  156 

75.  BENZIDINE  FROM  NITROBENZENE     ....  158 

76.  ORANGE  II        .      ...     ....     .     .  160 

77.  -ANTHRAQUINONE    ....;....  162 

78.  ALIZARIN  164 


vui 


LABORATORY    MANUAL    OF 
ORGANIC    CHEMISTRY 

EXPERIMENT  1 
FRACTIONAL   DISTILLATION 

Arrange  the  apparatus  as  shown  in  Fig.  I,  using  a 
500  cc.  distilling  flask,  a  thermometer,  a  condenser  and 
an  adapter.  The  distilling  flask  is  securely,  but  not  too 


tightly  clamped  above  the  side  tube.  The  side  tube 
should  extend  into  the  inner  tube  of  the  condenser  below 
the  level  of  the  water  in  the  surrounding  water  jacket. 
The  corks  should  be  well  bored  and  fit  tightly  and  the 
apparatus  arranged  so  that  the  liquid  never  comes  into 
contact  with  the  cork.  The  distilling  flask  should  rest 
in  a  circular  opening  (diam.  2  in.)  in  a  6  in.  square  of 
asbestos  board,1  which  should  extend  beyond  the  sides 

1  See  Identification  of  Pure  Organic  Compounds,  by  Mulliken,  vol.  I, 
pp.  221,  223. 

1 


of  the  distilling  flask.  It  should  be  made  to  fit  tightly 
in  the  opening  by  moistening  the  edge  of  the  opening 
and  rotating  the  flask  on  the  moistened  edge.  The 
ebullator  tube1  should  be  at  the  center  of  this  circular 
opening.  A  6  in.  square  of  wire  gauze,  which  is  to  be 
heated  by  means  of  a  Bunsen  burner,  is  placed  under  the 
asbestos  board  on  an  iron  ring.  The  gauze  should  be 
bent  down  so  that  there  is  about  a  quarter  of  an  inch 
ah-  space  between  it  and  the  flask.  Have  six  clean,  dry 
250  cc.  Erlenmeyer  flasks,  labeled  to  receive  the  frac- 
tions outlined  in  Table  I  (page  4). 

Put  200  cc.  of  distilled  water  and  200  cc.  of  alcohol 
(95%  ethyl  alcohol)  in  the  distilling  flask  and  thoroughly 
mix  them. 

First  Fradionation.  —  Heat  the  mixture  slowly  and  note 
the  temperature  at  which  it  begins  to  boil  (when  the 
first  drop  of  the  distillate  falls  into  the  receiver).  Distil 
the  mixture  slowly,  so  that  the  drops  falling  into  the 
receiver  are  distinct  and  can  be  counted  (90-100  per 
minute),  until  the  temperature  of  the  vapor  begins  to 
exceed  83°,  when  the  first  receiver  is  replaced  by  the 
second  one  without  stopping  the  distillation.  Collect 
the  distillate  in  this  receiver  until  the  temperature  begins 
to  exceed  88°  when  the  second  receiver  is  replaced  by  the 
third.  Continue  the  distillation,  collecting  the  distil- 
lates in  the  proper  receivers,  until  only  5-10  cc.  of  the 
liquid  remain  in  the  distilling  flask  when  the  distillation 
is  stopped. 

Measure  and  record  the  volumes  of  each  fraction  and 
of  the  residue  in  Column  1,  Table  I. 

Second  Fradionation.  —  Put  the  first  fraction  in  a  clean, 
dry  250  cc.  distilling  flask.  Distil  this  until  the  temper- 
ature begins  to  exceed  83°,  collecting  the  distillate  in  the 
receiver  just  emptied.  Note  that  all  of  the  fraction  does 
not  distil  over  at  this  temperature.  Stop  the  distilla- 
tion and  add  to  the  residue  in  the  distilling  flask  the 

1  See  Identification  of  Pure  Organic  Compounds,  by  Mulliken,  vol.  I, 
pp.  221,  223. 


second  fraction,  83-88°.  Fractionally  distil  this  mixture, 
collecting  the  distillate  in  receivers  1  and  2,  until  the 
temperature  begins  to  exceed  88°,  when  the  distillation  is 
again  stopped  and  fraction  3,  88-93°,  is  added.  Continue 
this  procedure  with  each  of  the  remaining  fractions  ob- 
tained in  the  first  fractionation.  Stop  the  distillation 
when  about  5  cc.  remain  in  the  distilling  flask. 

Measure  and  record  the  volumes  of  the  new  fractions 
and  of  the  residue  in  Column  2,  Table  I  (page  4). 

TABLE  I 


FRACTIONS 

DISTILLATIONS 

2 

3 

4 

5 

00  o 

83-88 
88-93 
93-98 
98  

Residues 

Totals 

Compare  the  volumes  of  the  same  fractions  in  the  two 
columns  and  draw  your  own  conclusions  regarding  the 
results.  What  would  happen  if  this  procedure  was  re- 
peated a  third  and  fourth  time? 

Define  the  boiling  point  of  a  liquid  and  explain  how 
the  boiling  point  of  a  pure  liquid  could  be  determined  by 
using  the  above  apparatus. 

For  further  information  regarding  all  kinds  of  distilla- 
tion and  for  methods  of  determining  boiling  points  the 
student  is  referred  to  Distillation;  Principles  and  Processes, 
by  S.  Young. 


EXPERIMENT  2 


FRACTIONAL  DISTILLATION  WITH  A 
HEMPEL  DISTILLING   TUBE 

Use  a  500  cc.  round  bottom  (R.B.)  flask  and  a  Hempel 

distilling  tube  (Fig.  II)  which  is  nearly  filled  with  small, 
hollow,  thin  walled  glass  balls  or  small 
glass  beads  and  connected  with  a 
thermometer  tube,  thermometer  and  a 
condenser.  The  R.B.  flask  should  rest 
in  the  circular  opening  in  the  square 
of  asbestos  board  and  the  wire  gauze 
is  placed  about  a  quarter  of  an  inch 
below  the  flask.  The  condenser  is 
fitted  with  an  adapter  as  in  the  first 
experiment.  Clean  and  dry  the  Erlen- 
meyer  flasks  used  as  receivers  in  the 
first  experiment  to  receive  the  distil- 
lates of  this  experiment. 

Put  200  cc.  of  distilled  water  and 
200  cc.  of  alcohol  in  the  R.B.  flask 
and  mix  thoroughly.  Use  an  ebullator 
tube  and  heat  slowly  and  note  the 
temperature  at  which  the  mixture 
begins  to  boil.  Distil  slowly  and  regu- 
larly, collecting  the  fractions  at  the 
same  temperature  intervals  as  in  Ex- 
periment 1,  in  the  proper  receivers. 
Stop  the  distillation  when  only  5-10  cc. 

remain  in  the  R.B.  flask. 

Measure  the  volumes  of  the  fractions  thus  obtained 

and  record  them  in  a  table. 

Compare  the  results  of  Experiments  1  and  2  and  draw 

your  own  conclusions  regarding  the  two  methods. 
6 


EXPERIMENT  3 
DETERMINATION   OF  THE   MELTING   POINT 

Use  the  Thiele  apparatus,  Dennis  modification.1 
The  pure  substance,  the  melting  point  of  which  is  to  be 
determined,  is  finely  ground  and  a  portion  of  it  put  in  a 
thin  walled  glass  tube  about  1  mm.  in 
diameter  and  6  cm.  long  which  is  sealed 
at  one  end.  These  melting  point  tubes 
can  be  obtained  from  the  stock  room  or 
can  be  made  by  drawing  out  a  piece  of 
soft  glass  tubing  in  the  flame  of  a  Bunsen 
burner.  A  small  amount  of  the  substance 
is  placed  in  the  open  end  of  the  tube 
and  is  forced  to  the  bottom  by  lightly 
rubbing  a  file  across  the  side  of  the  tube.  The  upper 
end  of  the  tube  is  fastened  to  the  thermometer  by 
means  of  a  small  rubber  band  (a  thin  section  of  rubber 
tubing  will  do)  or  a  platinum  wire,  so  that  the  substance 
is  opposite  the  mercury  bulb.  The  thermometer  bulb  is 
then  immersed  in  the  cone,  sulphuric  acid  which  should 
fill  the  Thiele  tube  so  as  to  just  close  the  opening  of  the 
side  tube.  The  thermometer  is  supported  in  the  appa- 
ratus by  means  of  a  cork,  part  of  which  is  cut  away  so 
that  the  graduations  of  the  thermometer  may  be  seen. 
Heat  slowly  with  a  small  flame  of  a  Bunsen  burner  at  the 
point  A.  Note  the  temperature  at  which  the  substance 
melts.  The  first  determination  only  gives  an  approxi- 
mate idea  of  the  melting  point  and  must  be  repeated  to 
obtain  the  true  melting  point. 

The  heating  may  be  fairly  rapid  until  within  about 
15-20°  of  the  melting  point  and  then  it  must  be  sloWj  3° 
a  minute,  timed,  until  the  substance  melts. 

The  sulphuric  acid  bath  can  be  used  up  to  230°.     For 
substances  with  higher  melting  points  a  mixture  of  70 
1  Jour.  Ind.  and  Eng.  Chem.,  12,  366  (1920). 
8 


parts  cone,  sulphuric  acid  and  30  parts  potassium  sulphate 
is  used. 

Determine  the  melting  points  of  naphthalene,  urea  and 
benzoic  acid  and  of  three  unknown  substances,  all  to 
be  obtained  from  the  instructor.  Wear  goggles. 

Record  the  observed  melting  points  in  the  following 
table  and  compare  them  with  the  correct  melting  points 
given  in  the  text  book. 

TABLE  II 


SUBSTANCES 

MELTING  POINTS 

Observed 

Correct 

Naphthalene 
Urea 
Benzoic  acid 
Unknown  1 
Unknown  2 
Unknown  3 

Define  the  melting  point  of  a  substance.  How  can 
it  be  shown  whether  a  compound  is  pure  by  determining 
its  melting  point? 

Can  the  melting  point  be  used  to  identify  a  compound? x 


EXPERIMENT  4 

DETERMINATION    OF   THE   BOILING   POINT   OF  A 
SMALL  AMOUNT   OF  LIQUID 

Use  the  Thiele  apparatus,  Dennis  modification,  placing 
a  few  drops  of  the  liquid  in  a  small  boiling  point  tube 
(a  thin  walled  glass  tube,  sealed  at  one  end,  5  mm.  in 
diameter  and  6  cm.  long).  A  melting  point  tube  should 
be  used  as  an  ebullator  tube. 

Determine  the  boiling  point  of  chloroform  and  of  an 
unknown  substance,  both  to  be  obtained  from  the  in- 
structor. Wear  goggles. 

1  See  Identification  of  Pure  Organic  Compounds,  by  Mulliken,  vol.  I, 
pp.  3-4. 

10 


EXPERIMENT  5 

METHANE 

(Marsh  Gas) 

.  Grind  together  intimately  2C  grams  of  fused  sodium 
acetate  and  40  grams  of  soda-lime.  Put  the  mixture  in 
a  clean,  dry  500  cc.  R.B.  flask.  The  flask  is  connected 
with  a  delivery  tube  as  shown  in  Fig.  IV.  A  square  of 


F7G.IV 


wire  gauze  is  placed  about  one  quarter  of  an  inch  below 
the  bottom  of  the  flask,  but  the  asbestos  board  is  not 
used.  Heat  the  mixture  with  a  triple  burner  collecting 
the  first  portions  of  the  gas  evolved  over  water  in  test 
tubes,  discarding  the  first  few  until  the  air  in  the  flask 
has  been  displaced.  When  the  gas  in  the  test  tube 
burns  quietly  when  ignited,  collect  the  methane  in  small 
glass  cylinders  over  water. 

Ignite  the  gas  in  one  of  the  cylinders  and  immediately 
after  the  gas  is  burned  add  2  cc.  of  lime  water  and  shake. 
Is  a  precipitate  formed?     Explain. 
12 


Add  1  cc.  of  bromide  water  to  another  cylinder  of  the 
gas  and  shake.  Is  there  any  color  change?  Explain. 

What  is  left  in  the  R.B.  flask?    Prove  it. 

In  what  volume  proportions  would  you  mix  oxygen 
and  methane  to  obtain  the  most  violent  explosion  when 
the  mixture  is  ignited?  Explain. 

Determine  the  properties  of  the  gas,  including  color, 
specific  gravity  (lighter  or  heavier  than  air),  solubility, 
flammability,  etc. 

CAUTION.  —  In  working  with  gases  all  joints  of  the  appa- 
ratus must  be  tight  before  beginning  the  experiment. 


14 


EXPERIMENT  6 
CHLOROFORM 

275  grams  of  bleaching  powder  and  800  cc.  of  water 
are  put  into  a  3  liter  balloon  flask  and  thoroughly  mixed. 
The  flask  is  fitted  with  a  cork  having  three  holes. 


Through  one  hole  passes  a  separately  funnel,  reaching 
to  the  bottom  of  the  flask;  through  the  second,  a  tube 
bent  in  two  places  and  also  reaching  to  the  bottom  of 
the  flask;  and  through  the  third,  the  exit  tube.  The 
exit  tube  is  connected  to  a  condenser,  which  is  attached 
to  an  adapter  and  the  other  tube  is  connected  to  a  source 
of  steam  (if  the  laboratory  desks  are  not  equipped  with 
steam,  a  small  copper  vessel  may  be  used  as  shown  in 
Fig.  V  or  a  R.B.  flask  may  be  used).  Add  very  gradu- 
ally and  carefully,  through  the  separatory  funnel,  a  mix- 
ture of  22  grams  of  acetone  and  70  cc.  of  water,  shaking 
the  flask  during  the  addition.  Chloroform  will  distil. 
Continue  the  shaking  until  chloroform  ceases  to  come 
over.  Then  heat  the  flask  and  its  contents  in  a  water 
bath,  at  the  same  tune  passing  steam  into  the  flask. 
16 


Continue  this  distillation  in  steam  as  long  as  chloroform 
distils  over  with  the  water.  The  chloroform  and  water 
are  collected  in  an  Erlenmeyer  flask.1 

The  chloroform  is  separated  from  the  water  by  means 
of  a  separatory  funnel.  Is  chloroform  heavier  or  lighter 
than  water?  The  chloroform  is  then  washed  with  dilute 
caustic  soda  solution  (?),  and  then  with  distilled  water (?). 
Remove  the  water  as  completely  as  possible  by  means 
of  the  separatory  funnel  and  dehydrate  the  chloroform 
by  allowing  it  to  stand  a  few  hours  with  some  granules 
of  calcium  chloride,  shaking  occasionally.  The  chlo- 
roform is  then  poured  off,  and  if  necessary  to  completely 
remove  the  calcium  chloride,  is  filtered,  and  then  dis- 
tilled, noting  the  boiling  point.  Save  a  specimen  of  the 
pure  substance. 

Determine  the  following  properties:  —  color,  odor,  taste, 
boiling  point,  specific  gravity  (lighter  or  heavier  than 
water),  solubility,  flammability,  etc. 

Does  an  aqueous  solution  of  chloroform  give  a  precipi- 
tate of  silver  chloride  when  treated  with  a  solution 
of  silver  nitrate?  Explain. 

1  The  reactions  for  the  preparation  of  chloroform  by  this  method 
should  be  written  after  acetone  and  chloral  have  been  studied. 


18 


EXPERIMENT  7 
IODOFORM 

Dissolve  10  grams  of  potassium  iodide  in  500  cc.  of 
water  and  add  2  grams  of  acetone.  To  this  mixture  add 
through  a  separatory  funnel  slowly  and  with  constant 
shaking,  a  dilute  solution  of  sodium  hypochlorite 1  as 
long  as  a  precipitate  is  formed.  Does  any  iodide  remain  in 
solution?  Allow  the  precipitate  to  settle,  decant  off  the 
supernatant  liquid,  wash  by  decantation  with  water  two 
or  three  times,  filter,  dry  on  drying  paper  and  crystal- 
lize from  alcohol.  To  crystallize  an  organic  solid  prepare 
a  saturated  solution  of  the  substance  in  the  boiling  sol- 
vent, using  a  reflux  condenser  if  necessary.  If  the  so- 
lution is  not  clear,  filter  while  hot.  Allow  the  solution 
to  cool  slowly  in  a  R.B.  flask  or  an  Erlenmeyer  flask. 
When  cold  filter  off  the  crystals  and  dry  them  in  the  an- 
on drying  paper.  Then  distil  off  some  of  the  solvent 
from  the  filtrate,  allow  the  solution  to  cool  and  filter  off 
the  crystals  formed.  Continue  this  procedure  until  all 
of  the  iodoform  has  been  crystallized.  Which  of  the 
fractions  thus  obtained  will  be  the  purest  and  why?  Save 
a  sample  of  the  pure  iodoform.  The  reactions  should  be 
written  after  acetone  and  chloral  have  been  studied. 

Determine  the  following  properties  of  the  pure  iodo- 
form:— melting  point,  solubility  in  water  and  alcohol; 
crystal  form,  odor  and  color. 

1  The  solution  of  sodium  hypochlorite  may  be  readily  made  by 
precipitating  all  the  calcium  in  a  saturated  solution  of  bleaching 
powder  with  a  solution  of  sodium  carbonate.  A  slight  excess  of 
sodium  carbonate  will  not  interfere. 


20 


EXPERIMENT  8 

ETHYL  BROMIDE 

(Hood) 

100  grams  of  powdered  potassium  bromide  are  placed 
in  a  500  cc.  distilling  flask,  and  a  cooled  mixture  of  45 
grams  of  90%  alcohol  and  100  grams  of  cone,  sulphuric 
acid  is  slowly  added,  keeping  the  flask  and  its  contents 
cold  by  holding  it  in  crushed  ice  and  shaking.  The  flask 
is  then  connected  with  a  condenser,  using  a  similar  ap- 
paratus to  that  shown  in  Fig.  I,  except  that  a  500  cc. 
suction  flask,  one  quarter  filled  with  ice  water,  is  fitted 
to  the  adapter  by  means  of  a  cork  and  used  as  a  receiver. 
The  side  tube  of  the  suction  flask  is  connected  with  rub- 
ber tubing  which  leads  to  the  hood  exhaust  (?).  Sur- 
round the  receiver  with  a  freezing  mixture  (ice  and  salt). 
Heat  the  distilling  flask  until  all  the  ethyl  bromide  has 
distilled.  The  ethyl  bromide  is  then  separated  from  the 
upper  layer  of  water,  washed  in  the  separatory  funnel, 
first  with  dilute  caustic  soda  solution  (?)  and  then  with 
water  (?).  It  is  dried  by  allowing  it  to  stand  in  a  glass 
stoppered  bottle  with  a  few  granules  of  calcium  chloride 
for  several  hours  with  occasional  shaking.  The  ethyl 
bromide  is  then  poured  into  a  small  distilling  flask  and 
distilled,  using  a  water  bath  and  an  ebullator  tube.  The 
entire  apparatus  must  be  clean  and  dry.  Note  the  boil- 
ing point  and  save  a  sample  of  the  pure  product. 

Determine  its  color,  taste,  odor,  specific  gravity  (lighter 
or  heavier  than  water)  and  flammability. 

Add  a  little  silver  nitrate  solution  to  some  of  the  ethyl 
bromide.  What  happens?  Boil  the  mixture  and  note 
what  happens.  Explain.  What  is  formed  when  ethyl 
bromide  is  boiled  with  water? 

What  remains  in  the  flask  in  which  the  ethyl  bromide 
was  made? 

22 


EXPERIMENT  9 
FERMENTATION   OF  GLUCOSE 

Dissolve  75  grams  of  glucose  in  1  liter  of  water  and 
add  30  cc.  of  a  solution  of  Pasteur  salts1  (?).  Put  the 
mixture  into  a  2  liter  flat  bottom  flask  and  connect  the 
flask  by  means  of  bent  glass  tubing  with  a  cylinder  con- 
taining lime  water.  The  tubing  extends  to  the  bottom 
of  the  cylinder  and  the  lime  water  is  protected  from  the 
air  by  a  layer  of  kerosene  (?).  Add  to  the  mixture  J^ 
cake  of  yeast  which  has  been  mixed  with  a  little  water, 
forming  a  thick  paste.  Allow  the  mixture  to  stand  for 
one  week  or  until  fermentation  ceases.  Filter  off  the 
supernatant  liquid.  Distil  500  cc.  of  this  slowly  through 
a  Hempel  tube,  testing  the  first  5  cc.  of  the  distillate  for 
flammability.  The  rest  of  the  distillate  (about  20  cc.) 
is  tested  for  alcohol  as  follows: — For  each  cc.  of  the 
cold  aqueous  solution  of  alcohol  used  add  2  drops  of 
sodium  hydroxide  solution  (1:10),  then,  drop  by  drop, 
add  a  concentrated  solution  of  iodine  in  a  solution  of 
potassium  iodide,  until  a  barely  perceptible  tint  of  yel- 
low, that  persists  after  standing  for  several  seconds,  re- 
mains. If  too  much  iodine  should  be  used,  cautiously 
add  just  enough  of  the  sodium  hydroxide  solution  to  de- 
stroy the  excess  color.  Let  the  mixture  stand  at  the 
temperature  of  the  laboratory  for  two  minutes  and  then 
shake.  Notice  whether  any  iodoform  separates.  If  no 

1  The  solution  of  Pasteur  salts  (based  on  an  analysis  of  the  inor- 
ganic constituents  of  the  yeast  plant)  is  made  as  follows: 

Potassium  phosphate 2 .00  parts 

Calcium  phosphate 0 .20  parts 

Magnesium  sulphate 0 . 20  parts 

Ammonium  tartrate 10 . 00  parts 

Water 857.60  parts 

24 


iodoform  separates  in  the  cold,  heat  the  solution  to  60° 
and  maintain  this  temperature  for  one  minute.  If  the 
solution  becomes  entirely  colorless  during  the  heating, 
add  just  enough  more  iodine  to  restore  the  trace  of  yel- 
low that  was  previously  present.  If  no  precipitate  ap- 
pears at  once,  set  the  tube  aside  for  two  minutes  before 
making  the  final  observation. 

What  is  formed  during  the  fermentation?  What  gas 
comes  off? 

See  the  article  on  "Fermentation"  hi  Thorpe's  Dic- 
tionary of  Applied  Chemistry. 


26 


EXPERIMENT  10 
ABSOLUTE  ALCOHOL 

Break  500  grams  of  good  quick  lime  into  small  lumps 
(not  powder)  and  put  it  in  a  3  liter  balloon  flask.  Add 
1  liter  of  95%  alcohol  and  exclude  the  moisture  of  the  air 
by  means  of  a  cork  carrying  a  tube  filled  with  calcium 
chloride.  Allow  the  alcohol  to  stand  over  the  quick  lime 
for  at  least  .two  or  three  days.  Connect  the  flask  with  a 
reflux  (upright)  condenser  and  heat  the  alcohol  to  boiling 
in  a  water  bath  for  three  hours.  The  upper  end  of  the  con- 
denser should  be  closed  by  a  cork  carrying  a  tube  filled 
with  calcium  chloride.  Then  fit  the  flask  with  a  cork 
carrying  a  thermometer  tube,  and  a  thermometer  and 
connect  with  a  condenser.  Heat  the  water  bath  and 
distil  off  the  alcohol,  noting  the  temperature  at  which  it 
boils  and  using  a  suction  flask  as  a  receiver.  Attach  a 
tube  filled  with  calcium  chloride  to  the  side  tube  of  the 
suction  flask.  Care  must  be  taken  to  prevent  the  al- 
cohol from  coming  into  contact  with  the  mositure  of  the 
air.  The  distillate  is  to  be  tested  with  an  alcoholmeter 
(by  the  assistant)  to  determine  the  percentage  of  alcohol. 
If  it  is  not  absolute,  repeat  the  process  with  the  distillate. 

Add  some  white,  anhydrous  copper  sulphate  to  some 
95%  alcohol  and  a  little  to  some  absolute  alcohol.  Note 
any  change  and  explain. 

Determine  the  properties  of  the  absolute  alcohol,  in- 
cluding odor,  color,  taste,  flammability.  Does  its  vapor 
mixed  with  air  explode?  Does  it  solidify  when  cooled? 
What  use  is  made  of  this  fact?  Is  alcohol  a  good  solvent? 

Put  the  absolute  alcohol  in  a  glass  stoppered  bottle 
and  save  for  future  use. 

Do  not  empty  the  waste  lime  into  the  sink;  a  suit- 
able container  will  be  found  in  the  court. 
28 


EXPERIMENT  11 
CALCIUM   ETHYL   SULPHATE 

Add  90  grams  of  cone,  sulphuric  acid  to  50  grams  of 
alcohol  in  a  small  flask  and  heat  the  mixture  on  a  boiling 
water  bath  for  30  minutes.  What  is  formed?  Cool  the 
mixture  and  then  pour  it  slowly  and  with  constant  stirring 
into  a  large  porcelain  dish  containing  crushed  ice  (?). 
Dilute  with  ice  water  to  about  a  liter  and  a  half.  Nearly 
neutralize  the  acid  by  means  of  slaked  lime,  adding  ice 
from  time  to  time  to  prevent  any  rise  of  temperature  (?). 
The  solution  is  then  filtered  by  the  method  of  reverse 
filtration.  The  apparatus  for  this  process  consists  of  a 
small  funnel  which  is  covered  with  muslin.  The  stem 
of  the  funnel  is  attached  by  rubber  tubing  to  a  500  cc. 
suction  flask  which  is  connected  with  the  suction  pump. 
The  funnel  is  placed  in  the  liquid  to  be  filtered  and  the 
suction  started.  The  filtered  liquid  is  quickly  drawn  into 
the  suction  flask.  The  residue  is  now  treated  with  500 
cc.  of  ice  water,  the  mixture  thoroughly  stirred  and  the 
liquid  filtered  off.  Clear  limewater  is  now  added  to  the 
combined  filtrates  to  alkaline  reaction  (?),  and  this  so- 
lution is  evaporated  to  crystallization  on  a  water  bath. 
Calcium  sulphate  will  separate  as  the  solution  is  con- 
centrated and  this  should  be  filtered  off.  Explain.  After 
all  the  calcium  sulphate  has  been  removed  the  solution 
is  allowed  to  crystallize  and  the  crystals  formed  are  fil- 
tered off,  using  a  Buchner  funnel.  The  process  is  re- 
peated with  the  mother  liquor.  The  crystals  are  drained 
thoroughly  on  the  "Buchner  funnel  and  dried  on  drying 
paper. 

Determine  the  color,  taste,  crystal  form,  and  solubil- 
ity of  the  crystals.  Save  a  sample  of  the  substance. 
30 


Does  the  salt  contain  water  of  crystallization?  Does  it 
contain  carbon?  Prove  both  statements. 

Dissolve  some  of  the  calcium  ethyl  sulphate  in  water 
and  add  a  solution  of  sodium  carbonate.  Explain  what 
takes  place.  Acidify  some  of  the  solution  of  calcium 
ethyl  sulphate  with  hydrochloric  acid  and  boil  the  solu- 
tion. Add  a  few  drops  of  barium  chloride  and  note  what 
takes  place.  Explain. 

What  is  formed  when  ethyl  sulphuric  acid  is  heated 
with  alcohol?  When  it  is  heated  with  water? 


EXPERIMENT  12 
ETHER 

Arrange  an  apparatus  as  shown  in  Fig.  VI,  using  a 
2  liter  balloon  flask.  The  receiver,  a  suction  flask,  is  sur- 
rounded by  a  freezing  mixture  (ice  and  salt)  and  rubber 


tubing  which  extends  to  the  floor  is  attached  to  the  side 
tube  (?).  Put  in  the  flask  170  grams  of  alcohol,  cool  the 
flask  and  add  slowly  306  grams  of  concentrated  sulphuric 
acid.  Wear  goggles 

32 


Heat  the  mixture  until  the  temperature  reaches  127°  to 
128°.  Then  cautiously  and  slowly  add  through  the  sepa- 
ratory  funnel  a  slow  stream  of  alcohol  in  the  form  of 
vapor  bubbles,  regulating  the  flow  of  alcohol  so  that  the 
temperature  is  kept  between  127°  and  128°  and  the  vol- 
ume of  liquid  in  the  flask  is  kept  constant.  When  200  cc. 
of  ether  have  been  obtained  the  operation  is  stopped. 
The  distillate  may  consist  of  two  layers,  and  contains, 
besides  ether,  water,  alcohol  and  sulphurous  acid.  The 
water  layer,  if  present,  is  removed  by  means  of  a  sep- 
aratory  funnel.  The  ether  is  washed  first  with  dilute 
caustic  soda  solution  (?),  then  with  small  quantities  of 
distilled  water.  The  ether  is  now  put  into  a  glass  stop- 
pered bottle  (?)  and  one  half  its  weight  of  granular  cal- 
cium chloride  is  added.  The  ether  is  allowed  to  stand 
for  several  days  and  then  filtered  into  a  clean,  dry  glass 
stoppered  bottle.  Save  a  small  specimen.  How  could 
you  prove  the  presence  of  ethylsulphuric  acid  in  the  flask 
in  which  ether  was  made? 

Determine  the  boiling  point,  specific  gravity,  color, 
taste  and  odor.  Is  it  a  good  solvent?  Does  water  dis- 
solve ether?  Does  ether  dissolve  water?  Put  1  cc.  of 
ether  in  an  iron  dish  and  ignite.  What  are  the  products 
of  the  combustion?  Write  out  the  equation.  In  a  thin 
walled  glass  test  tube  put  3  cc.  of  water  and  place  the 
tube  in  a  small  beaker  containing  ether.  Blow  air  from 
the  blast  over  the  surface  of  the  ether.  What  happens 
to  the  water  in  the  test  tube?  Explain.  Place  a  little 
ether  on  the  hand  and  blow  over  it. 

CAUTION.  —  Never  boil  ether  over  a  free  flame;  and  in 
working  with  it,  always  carefully  avoid  the  neighborhood  of 
flames.  In  distilling  it  in  a  water  bath,  do  not  heat  the 
water  to  boiling. 


34 


EXPERIMENT  13 
ALDEHYDE 

Dissolve  5  grams  of  potassium  bichromate  in  water 
and  slowly  add  15  cc.  of  cone,  sulphuric  acid.  Is  there 
any  color  change?  Cool  and  add  a  few  cubic  centimeters 
of  alcohol.  Warm.  Is  there  any  color  change?  Note 
the  odor.  What  is  formed?  How  could  it  be  obtained 
from  the  solution?  What  would  be  left  in  the  solution? 
Write  out  the  equations  representing  each  step. 

Obtain  50  cc.  of  paraldehyde  from  the  stock  room. 
Put  it  in  a  150  cc.  round  bottom  flask,  add  2  drops  only 
of  cone.  C.P.  sulphuric  acid  and  distil  through  a  Hempel 
tube,  keeping  the  temperature  in  the  thermometer  tube 
below  30°.  Use  the  same  type  of  receiver  as  was  used 
for  ether,  and  surround  it  with  a  freezing  mixture  (?). 
What  distils  over?  Determine  its  boiling  point,  taste, 
odor,  color  and  flammability.  Compare  the  odor  with 
that  obtained  when  alcohol  was  warmed  with  the  bi- 
chromate mixture.  Is  aldehyde  lighter  or  heavier  than 
water?  Does  it  dissolve  iodine  and  sulphur?  Heat  a 
a  few  drops  of  the  aldehyde  with  caustic  potash  solution, 
noting  any  change  of  color  and  odor.  Explain.  Save  a 
small  specimen  of  the  aldehyde  and  use  the  remainder 
hi  the  following  experiments. 

CAUTION.  —  Aldehyde  is  very  volatile  and  flammable;  care 
must,  therefore,  be  taken  to  avoid  the  presence  of  a  free  flame 
when  working  with  it. 


36 


51997 


EXPERIMENT  14 

ALDEHYDE   AMMONIA 

(Hood) 

To  5  cc.  of  the  aldehyde  add  20  cc.  of  anhydrous  ether, 
cool  in  a  freezing  mixture,  and  saturate  with  dry  ammonia 
gas.  (The  latter  is  easily  obtained,  in  case  a  tank  of 
ammonia  is  not  available,  by  heating  a  strong  solution 
of  ammonia  and  passing  the  evolved  gas  through  an  empty 
cylinder  and  then  through  a  cylinder  containing  soda 
lime.)  Note  result  and  explain.  Filter  off  the  crystals, 
dry  and  save  a  specimen.  More  crystals  may  be  obtained 
by  evaporating  the  ethereal  solution.  Heat  some  of  the 
aldehyde  ammonia  with  dilute  hydrochloric  acid  and 
note  the  odor.  Explain. 


EXPERIMENT  15 

METALDEHYDE   AND   PARALDEHYDE 

(Hood) 

Cool  5  to  10  cc.  of  the  aldehyde  in  a  test  tube  in  a 
freezing  mixture,  and  pass  in  a  few  bubbles  of  dry  hydro- 
chloric acid  gas.  (The  latter  may  be  obtained  by  heating 
concentrated  hydrochloric  acid  and  drying  the  gas  evolved 
by  passing  it  through  a  wash  bottle  containing  cone, 
sulphuric  acid.)  It  is  essential  that  the  aldehyde,  ap- 
paratus and  hydrochloric  acid  gas  should  be  absolutely 
dry.  What  happens?  Explain.  Filter  off  the  crystals 
and  dry  them.  Save  a  specimen.  Cool  the  nitrate  in 
a  freezing  mixture  of  crushed  ice  and  cone,  hydrochloric 
acid.  Note  result  and  explain.  Save  a  specimen. 


38 


EXPERIMENT  16 
DETECTION   OF  ALDEHYDE 

To  10  cc.  of  an  approximate  N/10  silver  nitrate  so- 
lution, add  cautiously  drop  by  drop  a  dilute  (3N)  solu- 
tion of  ammonia,  until  the  silver  oxide  first  precipitated 
is  just  dissolved.  Avoid  any  excess  of  ammonia.  An 
ammoniacal  solution  of  silver  oxide  is  thus  obtained. 

Clean  a  test  tube  thoroughly  by  boiling  some  cone, 
nitric  acid  in  it,  pouring  out  the  acid  and  washing  with 
distilled  water.  Half  fill  the  cleaned  test  tube  with  the 
ammoniacal  silver  oxide  solution  and  add  a  drop  of  a 
dilute  aqueous  solution  of  aldehyde.  Place  the  test 
tube  in  a  beaker  ef  cold  water  and  heat  the  water  hi  the 
beaker  to  boiling.  Note  the  result  and  explain.  This 
reaction  is  characteristic  of  the  aldehyde  group.  What 
practical  use  is  made  of  this  reaction?  What  aldehyde 
is  used?  How  delicate  is  this  reaction  as  a  test  both  for 
aldehyde  and  for  silver? 

See  Roscoe  and  Schorlemmer's  Treatise  on  Chemistry, 
vol.  Ill,  p.  478. 


40 


EXPERIMENT  17 
FORMIC  ACID 

(Hood) 

Into  a  500  cc.  dry  distilling  flask  put  200  grams  of 
crystallized  oxalic  acid  and  200  grams  of  anhydrous 
glycerol  (or  "Glycerol  Residues,"  see  below).  Insert  a 
thermometer  through  the  cork,  so  that  the  bulb  dips 
below  the  surface  of  the  glycerol,  and  connect  the  flask 
with  a  condenser  and  a  receiver.  Heat  gently  with  a 
burner,  keeping  the  temperature  of  the  liquid  between 
100°-115°.  What  gas  is  given  off?  When  this  gas  ceases 
to  be  evolved,  and  after  the  contents  of  the  flask  have 
cooled  to  75°,  add  50  grams  more  of  the  crystallized 
oxalic  acid,  and  heat  as  before.  Repeat  this  addition  of 
oxalic  acid  until  100  cc.  of  distillate  have  collected  in  the 
receiver.  Put  the  glycerol  into  the  bottle  marked 
"Glycerol  Residues,"  and  set  aside  25  cc.  of  the  distil- 
late for  the  experiments  given  below.  Divide  the  rest 
into  three  portions.  Neutralize  one  portion  with  chalk 
or  slaked  lime,  filter,  evaporate  to  crystallization,  and 
save  specimen  of  the  calcium  salt.  Warm  the  second 
portion  with  a  slight  excess  of  lead  carbonate  or  oxide, 
decant  through  a  filter,  and  extract  the  precipitate  two 
or  three  times  with  boiling  water  (?).  Evaporate  the 
combined  filtrates  to  crystallization  and  save  a  specimen 
of  the  lead  salt.  Heat  the  third  portion  until  saturated 
with  freshly  precipitated  copper  hydroxide  (obtained  by 
precipitating  a  solution  of  copper  sulphate  with  caustic 
soda  solution  and  washing  the  precipitate  thoroughly  with 
water),  filter,  evaporate  the  filtrate  to  crystallization, 
and  save  a  specimen  of  the  copper  salt. 

With  the  25  cc.  of  the  distillate  perform  the  following 
experiments: — 

(a)  Heat  a  small  quantity  with  some  mercuric  oxide  and 
note  the  result.     Explain. 
42 


(6)   Heat  some  with  a  solution  of  silver  nitrate  and  de- 
scribe and  explain  what  takes  place. 
(Explain  why  these  two  reactions  are  characteristic 

of  formic  acid.) 

How  is  formic  acid  made  from  chloroform? 
Describe  both  the  physical  and  chemical  properties  of 
the  acid  and  all  the  salts  made;    save  specimens  of  all 
the  salts  and  of  the  distillate. 

(Use  the  material  in  the  bottle  marked  "Glycerol 
Residues"  to  start  with,  if  it  is  available,  instead  of 
glycerol  itself,  and  add  only  50  grams  of  oxalic  acid  at 
a  time.) 


44 


EXPERIMENT  18 

ACETIC  ACID 

(Hood) 

150  grams  of  fused  sodium  acetate  are  powdered  and 
put  into  a  500  cc.  dry  distilling  flask.  The  flask  is  cooled, 
and  180  grams  of  concentrated  sulphuric  acid  (sp.  gr. 
1.842)  are  gradually  added  through  a  funnel  tube  reach- 
ing to  the  bottom  of  the  flask.  The  flask  is  then  con- 
nected with  a  condenser  and  receiver  and  heated.  The 
distillate  is  subjected  to  fractional  distillation,  using  a 
short  Hempel  distilling  tube,  or  a  distilling  flask,  with 
a  column  of  glass  balls  in  the  neck  (see  figure),  and  an 
ebullator  tube. 

First  an  aqueous  acid  passes  over 
and  is  collected  separately,  but  be- 
tween 117°  and  119°  the  anhydrous 
acid  distils.  Cool  this  distillate  (be- 
tween 117°-119°)  with  ice  water,  and 
note  what  takes  place.  Save  speci- 
men of  the  glacial  acid.  Why  is  the 
first  distillate  not  anhydrous? 

A  portion  of  the  first  distillate  of  the 
aqueous  acid  is  carefully  neutralized 
with  caustic  soda  solution  and  divided 
into  four  portions.  One  portion  is 
heated  to  boiling,  and  then  a  slight  ex- 
FIG.  vn  cess  Of  mercurous  nitrate  solution  added. 

Explain  what  takes  place.  The  second  portion  is  also 
heated  to  boiling,  and  a  tolerably  concentrated  solution 
of  silver  nitrate  added.  Note  what  takes  place.  Explain. 
The  third  portion  is  evaporated  to  dryness,  on  a  steam 
or  water  bath,  with  some  powdered  arsenic  trioxide,  and 
a  little  of  the  resulting  mass  heated  in  a  test  tube  when 
46 


the  characteristic  odor  of  cacodyl  oxide  is  given  off.  Ex- 
plain. To  the  fourth  portion  add  a  few  drops  of  cone, 
sulphuric  acid  and  some  alcohol,  and  heat.  Notice  the 
odor.  Explain. 

Show  how  you  could  distinguish  between  formic  and 
acetic  acids. 

Describe  the  properties  of  acetic  acid,  and  give  some 
of  the  methods  by  which  this  substance  may  be  detected 
in  solution. 

EXPERIMENT  19 

SEPARATION  OF  IRON  AND  ALUMINUM  FROM 
MANGANESE,  ZINC,  ETC. 

Make  up  a  solution  containing  ferric  chloride,  alumi- 
num, manganese,  zinc,  cobalt,  and  nickel  chlorides. 
Nearly  neutralize  any  free  acid  present  with  a  solution 
of  sodium  carbonate  (?).  If  a  precipitate  is  formed  dis- 
solve by  adding  a  small  quantity  of  acetic  acid.  Add 
enough  of  a  concentrated  solution  of  sodium  acetate  to 
convert  all  the  metals  present  into  acetatas  (taking  care 
to  avoid  a  large  excess  of  the  reagent),  and  boil  the  so- 
lution. Note  what  takes  place.  What  is  volatilized? 
Explain.  Filter  off  the  precipitate  and  test  the  filtrate 
for  iron,  aluminum,  and  the  other  metals.  Draw  your 
own  conclusions  from  the  results,  and  show  how  these 
facts  could  be  utilized  in  analytical  chemistry.  Could 
you  separate  ferrous  from  ferric  chloride  by  this  method? 
Explain. 


48 


EXPERIMENT  20 

ACETYL   CHLORIDE 

(Hood) 

20  grams  of  glacial  acetic  acid  are  put  into  a  dry  (?) 
250  cc.  round  bottom  flask,  the  flask  cooled  with  ice 
water,  and  30  grams  of  phosphorus  trichloride  (weigh 
this  under  the  hood  (?))  are  gradually  added,  with  con- 
stant shaking.  Connect  the  flask  with  a  return  condenser, 
and  heat  it  in  a  water  bath  to  50°-60°  C.  until  almost  all 
the  hydrochloric  acid  gas  has  been  expelled.  The  con- 
denser is  then  turned  down  and  the  acetyl  chloride  dis- 
tilled off,  care  being  taken  to  protect  the  distillate  from 
the  action  of  the  moisture  in  the  air  by  means  of  a  tube 
containing  calcium  chloride.  The  distillate  is  then  placed 
in  a  small,  dry  distilling  flask,  and  redistilled  with  the 
same  precautions  as  before.  Note  the  boiling  point. 

What  remains  in  the  flask  in  which  the  acetyl  chloride 
was  made? 

Determine  the  properties  of  acetyl  chloride,  including 
color,  odor,  and  action  on  moist  air. 

Treat  a  few  cubic  centimeters  of  absolute  alcohol  with 
acetyl  chloride  and  note  what  takes  place.  What  gas  is 
given  off?  What  is  formed?  Explain.  Repeat  the  ex- 
periment, using  water  instead  of  alcohol.  Explain. 
What  conclusions  would  you  draw  regarding  the  relation 
between  water  and  alcohol  from  this  experiment?  What 
use  is  made  of  acetyl  chloride  in  the  laboratory? 


50 


EXPERIMENT  21 

ACETIC  ANHYDRIDE 

(Hood) 

20  grams  of  finely  powdered  anhydrous  sodium  acetate 
are  placed  in  a  dry  250  cc.  distilling  flask.  A  small  sep- 
aratory  funnel  is  fitted  into  the  flask  and  the  flask  is 
connected  with  a  condenser,  adapter  and  a  suction  flask 
as  a  receiver,  the  side  arm  being  attached  to  a  tube 
filled  with  calcium  chloride  (?).  15  grams  of  acetyl 
chloride  are  now  added  slowly,  drop  by  drop,  through 
the  separatory  funnel.  If  the  acetyl  chloride  is  added 
too  fast  it  will  distil  over  into  the  receiver  unchanged. 
It  should  then  be  poured  back  into  the  separatory  funnel 
and  added  more  slowly.  Shake  constantly  while  adding 
the  acetyl  chloride.  Then  remove  the  separatory  funnel, 
fit  the  flask  with  a  cork  and  distil  the  anhydride.  The 
distillate  is  freed"  from  any  acetyl  chloride  that  may  be 
present  by  distillation  with  3  grams  of  finely  powdered 
anhydrous  sodium  acetate  and  the  boiling  point  of  the 
anhydride  is  noted.  Determine  the  physical  properties 
of  the  anhydride.  Save  a  specimen  in  a  sealed  tube. 

To  5  cc.  of  water  add  a  few  drops  of  acetic  anhydride. 
Note  what  happens.  Warm  the  mixture  and  note  what 
happens.  Explain. 

To  5  cc.  of  water  and  a  few  drops  of  the  anhydride, 
add  a  little  caustic  soda  solution.  Shake,  note  what 
happens  and  explain. 

To  2  cc.  of  alcohol  add  1  cc.  of  the  anhydride  and  heat 
gently  for  several  minutes.  Treat  with  water  and  make 
the  solution  slightly  alkaline.  Note  the  odor.  What  is 
the  substance  formed?  Explain. 

Compare  the  reactions  with  water  and  alcohol  with 
the  corresponding  reactions  with  acetyl  chloride. 

What  use  is  made  of  acetic  anhydride  in  the  laboratory? 
52 


EXPERIMENT  22 
ETHYL  ACETATE 

(Acetic  Ether) 

Arrange  an  apparatus1  like  that  used  in  the  prepara- 
tion of  ether  (see  Experiment  12).  Into  the  round  bot- 
tom flask  put  50  grams  of  cone,  sulphuric  acid  and  50 
grams  of  absolute  alcohol  (95%  will  do).  Heat  till  the 
temperature  reaches  130°-140°  C.,  and  then  add  gradually 
through  the  separatory  funnel  a  mixture  of  30  grams  of 
glacial  acetic  acid  and  30  grams  of  absolute  alcohol 
(95%  will  do). 

Separate  the  crude  acetic  ether  from  the  water  and 
wash  with  caustic  soda  solution;  dehydrate  in  the  usual 
manner  with  fused  calcium  chloride,  and  subject  to  frac- 
tional distillation. 

Determine  color,  taste,  odor,  boiling  point,  specific 
gravity,  solubility  and  flammability.  Is  there  any  anal- 
ogy in  the  method  of  preparation  of  this  acetic  ether  and 
the  method  used  to  make  ordinary  ether?  What  else  is 
formed  here  besides  acetic  ether?  Save  a  small  specimen. 
Use  20  grams  of  the  ethyl  acetate  in  the  following  ex- 
periment. 

liter  flask. 


54 


EXPERIMENT  23 
SAPONIFICATION 

Calculate  the  amount  of  solid  caustic  soda  necessary 
to  decompose  20  grams  of  the  ethyl  acetate  made  in 
Experiment  22,  assuming  that  the  caustic  soda  contains 
10  per  cent  of  water.  Dissolve  this  amount  plus  5  grams 
excess  in  300  cc.  of  water  in  a  500  cc.  round  bottom  flask 
and  add  the  20  grams  of  ethyl  acetate.  Connect  the 
flask  with  a  reflux  condenser  and  heat  the  mixture  to 
boiling  for  one  hour  or  until  the  odor  of  ethyl  acetate 
has  disappeared.  Explain  what  takes  place.  Why  is 
this  process  called  saponification? 

Then  distil  off  100  cc.  of  the  liquid  and  examine  the 
distillate.  What  does  it  contain  and  how  is  this  shown? 

Acidify  the  mixture  in  the  flask  when  cold  with  dilute 
sulphuric  acid  and  again  distil.  What  passes  over  now  ? 
Does  the  distillate  have  an  acid  reaction?  How  could 
the  amount  of  the  substance  present  in  the  distillate 
be  determined? 

Given  a  mixture  of  ethyl  acetate  and  ethyl  alcohol  ex- 
plain how  the  amount  of  each  could  be  determined. 


56 


EXPERIMENT  24 

POTASSIUM   CYANIDE1 

(Hood) 

50  grams  of  potassium  ferrocyanide  are  dehydrated  by 
heating  the  powdered  salt  in  a  porcelain  dish  in  an  air 
bath  at  110°  until  it  ceases  to  lose  weight.  The  dehy- 
drated salt  is  powdered  again  and  placed  in  an  iron  or 
copper  retort  provided  with  a  cover,  asbestos  paper  gas- 
ket, and  an  outlet  tube.  Exclude  air  from  the  retort  by 
keeping  the  outlet  tube  under  water.  Protect  the  table 
top  by  means  of  a  square  of  asbestos  board  placed  on 
glass  rods.  Heat  the  retort  to  red  heat  with  a  good 
triple  burner.  A  gas  comes  off;  collect  some  and  see  if 
it  will  support  combustion.  Continue  the  heating  until 
the  gas  ceases  to  be  evolved.  Then  remove  the  outlet 
tube  from  the  water  and  cool  the  retort.  Take  out  the 
contents  of  the  retort  and  grind  in  a  mortar  to  a  fine 
powder.  Put  the  powder  in  a  flask  and  extract  twice 
with  boiling  methyl  alcohol,  using  a  reflux  condenser  and 
a  water  bath.  Use  100  cc.  of  methyl  alcohol  for  each 
extraction.  Filter  the  alcoholic  extracts  while  hot  and 
allow  them  to  cool.  If  crystals  separate,  filter  them  off 
and  dry  them.  Otherwise,  distil  off  some  of  the  methyl 
alcohol  until  crystals  doseparate  when  the  solution  is  cooled. 
Continue  with  the  mother  liquors  until  a  maximum  yield 
is  obtained.  Save  a  small  specimen  of  the  crystals. 

Determine  the  solubility  and  the  crystal  form  of  the 
salt.  Does  it  resemble  potassium  chloride  in  any  way? 
Has  it  an  odor?  Explain.  Is  the  salt  deliquescent?  Does 
the  aqueous  solution  decompose  on  boiling?  What  is 
formed?  Is  the  aqueous  solution  alkaline?  Explain. 
Fuse  some  of  the  salt  in  a  test  tube  with  a  little  lead 
oxide  (PbO).  Note  what  happens  and  explain.  Does 
an  aqueous  solution  of  the  salt  dissolve  the  cyanides  of 
silver  and  gold?  What  use  is  made  of  this  property? 
1  See  Thorpe's  Dictionary  of  Applied  Chemistry,  article  on  Cyanides. 
58 


Does  an  aqueous  solution  of  the  salt  dissolve  gold?  Write 
the  equation. 

CAUTION. — Potassium  cyanide  is  extremely  poisonous  and 
great  care  must  be  taken  in  working  with  it.  The  hands 
should  be  thoroughly  washed  after  handling  the  salt  and  the 
finger  nails  should  be  cleaned. 

Methyl  alcohol  is  also  poisonous  and  care  must  be  taken 
not  to  breathe  its  vapor. 

EXPERIMENT  25 
POTASSIUM   FERRICYANIDE 

Dissolve  26  grams  of  crystallized  potassium  ferro- 
cyanide  in  200  cc.  of  distilled  water,  and  add  8  cc.  of 
concentrated  hydrochloric  acid.  Into  this  solution  drop 
slowly,  from  a  separatory  funnel,  a  solution  of  2  grams 
of  potassium  permanganate  in  300  cc.  of  distilled  water. 
The  reaction  is  complete  when  a  drop  of  the  solution 
added  to  a  solution  of  ferric  chloride  gives  a  brownish 
red  color  but  no  precipitate.  //  add,  neutralize  the  ex- 
cess of  hydrochloric  acid  with  chalk,  filter,  and  evaporate 
on  a  water-bath  to  crystallization. 

Save  a  specimen  of  the  salt,  and  determine  color,  taste, 
crystal  form,  solubility,  etc.,  of  the  potassium  ferricyanide. 
Does  the  solution  decompose  in  the  light?  What  use  is 
made  of  this  salt?1 

Is  it  a  good  oxidizing  agent?  Try  it  in  alkaline  so- 
lution with  some  lead  oxide.  Does  potassium  ferro- 
cyanide  contain  water  of  crystallization?  Does  the  ferri- 
cyanide? To  a  small  quantity  of  a  saturated  solution 
of  the  ferrocyanide  in  a  test  tube  add  an  equal  volume 
of  fuming  hydrochloric  acid.  Add  two  or  three  volumes 
of  fuming  hydrochloric  acid  to  one  volume  of  a  saturated 
solution  of  the  ferricyanide.  Explain  what  takes  place 
in  each  case. 

1  See  Thorpe's  Dictionary  of  Applied  Chemistry,  article  on  Photog- 
raphy, vol.  IV,  p.  231. 

60 


EXPERIMENT  26 » 
POTASSIUM    CYANATE 

Mix  intimately  100  grams  of  dehydrated  powdered  po- 
tassium ferrocyanide  with  75  grams  of  dry2  powdered 
potassium  bichromate,  which  has  been  previously  melted. 
A  little  of  this  mixture  is  placed  in  a  porcelain  or,  better, 
an  iron  dish  and  heated  (considerably  below  redness) 
until  the  mixture  begins  to  glow  and  blackens.  The 
rest  of  the  mixture  is  then  added  little  by  little,  each  quan- 
tity being  allowed  to  blacken  before  the  next  is  added 
(complete  oxidation  of  the  cyanide  to  cyanate  is  thus  ef- 
fected). After  cooling,  the  contents  of  the  dish  are  ex- 
tracted several  times  with  boiling  alcohol  (450  cc.  of  80% 
alcohol  and  50  cc.  of  methyl  alcohol).  Filter,  and  cool 
the  alcoholic  solution  to  0°.  Filter  off  the  crystals  formed, 
using  a  Buchner  funnel  and  suction  pump.  Dry  on  dry- 
ing paper.  Continue  the  extraction  until  the  black  mass 
is  exhausted. 

Save  a  small  specimen  of  the  cyanate.  Determine 
crystal  form,  solubility,  color,  taste,  odor,  etc.  Does  the 
aqueous  solution  decompose  on  standing?  What  are  the' 
products?  Add  some  dilute  sulphuric  acid  to  a  solution 
of  the  cyanate,  and  explain  what  takes  place.  Is  there 
any  resemblance  between  potassium  cyanate  and  potas- 
sium hypochlorite?  Show  this  by  the  method  of  forma- 
tion, one  from  cyanogen  and  the  other  from  chlorine  and 
a  solution  of  potassium  hydroxide.  Prepare  20  grams  of 
the  cyanate  and  keep  it  for  the  preparation  of  urea, 
Experiment  42. 

xRead  carefully  the  directions  in  the  Chemical  News,  vol.  32,  p.  99. 
8Heat  some  in  a  test  tube,  and  see  that  it  gives  off  no  water. 


EXPERIMENT  27 
POTASSIUM  THIO  CYAN  ATE 

An  aqueous  solution  of  13  grams  potassium  cyanide 
is  boiled  with  6.4  grams  flowers  of  sulphur  in  a  round 
bottomed  flask  connected  with  a  reflux  condenser,  until 
all  the  sulphur  is  dissolved.  Filter  the  solution  and  evap- 
orate to  crystallization.  Drain  off  the  crystals  and  re- 
peat the  evaporation  with  the  mother  liquor. 

Determine  properties  of  the  salt,  including  color,  taste, 
odor,  crystal  form,  solubility,  and  melting  point.  What 
takes  place  when  the  crystals  are  left  exposed  to  the  air? 
Is  there  any  analogy  between  the  formation  of  the  cyanate 
(Experiment  26)  and  the  thiocyanate?  What  use  is  made 
of  the  thiocyanate  in  the  analytical  laboratory?  Heat 
some  of  the  salt  in  a  porcelain  crucible  and  note  the 
changes  in  color.  Let  cool  and  note  any  changes. 

Save  a  specimen  of  the  potassium  salt. 

Dissolve  5  grams  of  potassium  thiocyanate  in  water, 
and  note  any  change  in  the  temperature  of  the  water. 
Explain. 


64 


EXPERIMENT  28 
AMMONIUM  THIOCYANATE 

Mix  60  grams  of  alcohol  (95%),  80  grams  of  ammonia 
solution,  and  35  to  40  grams  of  carbon  bisulphide,1  and 
allow  to  stand  in  a  glass  stoppered  bottle  until  all  the  car- 
bon bisulphide  has  dissolved.  The  process  may  be  has- 
tened by  shaking  the  bottle  from  time  to  time,  relieving 
any  pressure  by  removing  the  stopper.  When  all  the 
carbon  bisulphide  has  dissolved,  evaporate  the  solution 
at  a  gentle  heat  on  a  steam  or  water  bath  (Hood)  to  one 
third  of  the  original  volume.  What  goes  off?  Filter  off 
any  sulphur  that  may  separate  out,  while  the  solution  is 
hot.  On  cooling,  ammonium  thiocyanate  crystallizes  out. 
Filter  off  the  crystals  and  repeat  the  evaporation  with 
the  mother  liquor. 

Determine  crystal  form,  solubility,  color,  taste,  odor, 
and  melting  point  of  the  salt.  How  is  thiourea  made 
from  ammonium  thiocyanate? 

Save  a  specimen  of  the  salt. 


EXPERIMENT  29 
ALDEHYDE 

(Hood) 

Mix  equal  weights  (1  gram)  of  dry  calcium  formate 
and  dry  calcium  acetate.  Distil  from  a  test  tube  fitted 
with  a  delivery  tube.  Collect  some  of  the  distillate  in 
water.  What  does  the  water  contain?  Prove  it  by  mak- 
ing a  silver  mirror. 

1  Carbon  bisulphide  is  very  flammable.  In  working  with  it  always 
avoid  any  flames. 


EXPERIMENT  30 
PALMITIC    ACID,    STEARIC    ACID    AND    GLYCEROL 

(Saponification  of  Fats) 

Heat  10  grams  of  solid  caustic  soda  in  a  small  flask 
with  20  cc.  of  water  until  it  is  all  in  solution  and  add 
150  cc.  of  alcohol.  Melt  in  a  porcelain  dish  on  a  water  bath 
10  grams  of  lard  and  then  add  to  it  the  alcoholic  solution 
of  caustic  soda.  Evaporate  to  a  syrupy  consistency  on 
a  water  bath,  with  constant  stirring,  and  then  allow  the 
mass  to  cool.  Convince  yourself  that  the  substance  left 
is  soap  (?). 

Is  it  a  hard  or  a  soft  soap?  Explain.  How  is  a  soft 
soap  converted  into  a  hard  soap?  Dissolve  a  little  of  the 
soap  in  water  and  filter  if  necessary.  Divide  the  solution 
into  three  portions,  and  add  to  the  first  portion  a  few  drops 
of  a  solution  of  calcium  sulphate,  to  the  second  a  few 
drops  of  a  solution  of  magnesium  sulphate,  and  to  the 
third  a  few  drops  of  a  solution  of  calcium  acid  carbonate. 
Explain  what  happens  in  each  case. 

What  is  meant  by  the  terms  permanent  and  temporary 
hardness  of  water?  How  can  the  hardness  of  water  be 
determined?  How  could  a  hard  water  be  made  soft? 

Save  a  small  specimen  of  the  soap  and  dissolve  the  rest 
in  a  liter  of  hot  water.  Cool.  Be  sure  that  all  of  the 
soap  is  in  solution  and  then  acidify  with  dilute  sulphuric 
acid.  What  is  the  precipitate  formed?  Filter  off  the 
precipitate,  wash  with  water,  dry  and  recrystallize  it  from 
alcohol.  Prove  that  the  substance  is  an  acid.  Save  a 
specimen. 

Neutralize  the  acid  filtrate  exactly  with  a  solution  of 

sodium  hydroxide  and  evaporate  it  to  dryness.     Extract 

the  residue  with  absolute  alcohol  several  times  until  it  is 

exhausted,  filtering  the  alcoholic  solutions.     Combine  the 

68 


alcoholic  filtrates  and  distil  off  the  alcohol,  using  a  water 
bath.  What  is  the  syrup  which  remains? l  Save  a 
specimen. 

Determine  color,  taste,  odor,  solubility  of  glycerol.  Is 
it  hygroscopic?  Can  it  be  distilled  under  ordinary  pres- 
sure? What  is  its  boiling  point?  Does  glycerol  dissolve 
caustic  potash,  lead  oxide  (PbO),  or  calcium  oxide? 
Explain. 

1  In  order  to  test  the  syrup  for  glycerol:  Make  a  borax  bead,  and 
when  cold  moisten  it  with  some  of  the  syrup.  Heat  the  bead  in  the 
flame  of  a  Bunsen  burner.  If  glycerol  is  present  the  flame  will  be 
colored  green.  Explain. 


70 


EXPERIMENT  31 

OXALIC  ACID 

(Hood) 

In  a  long  necked  flask,  of  about  1  liter  capacity,  heat 
gently  25 1  grams  of  cane  sugar  and  125  grams  of  cone, 
nitric  acid.  Gases  are  evolved.  Explain.  After  the  re- 
action is  over,  evaporate  the  solution  to  crystallization 
and  let  cool.  Filter  or  pour  off  the  mother  liquor  and  add 
to  it  a  smaller  quantity  of  nitric  acid,  heat,  and  again 
evaporate  to  crystallization.  Filter  off  the  crystals, 
drain  completely  on  a  Buchner  funnel  and  recrystallize 
from  distilled  water. 

Determine  color,  taste  (poison),  odor,  solubility,  crystal 
form,  etc.,  of  the  acid.  Is  it  a  strong  acid?  (See  Ex- 
periment 41.)  Does  it  contain  water  of  crystallization? 
Prove  it.  Does  it  sublime  when  heated?  Is  it  a  reducing 
agent?  Why?  What  does  the  acid  yield  when  heated 
with  glycerol?  Neutralize  a  solution  of  oxalic  acid  with 
ammonia  and  add  a  solution  of  calcium  chloride.  What 
is  formed?  How  is  oxalic  acid  determined  quantitatively? 

What  does  oxalic  acid  give  when  heated  with  cone, 
sulphuric  acid? 

Dissolve  some  oxalic  acid  in  water  and  add  some  dilute 
sulphuric  acid  (?).  Now  run  in  a  little  of  a  dilute  solution 
•of  potassium  permanganate  and  note  what  takes  place. 
What  becomes  of  the  permanganate  and  of  the  oxalic 
acid?  Write  out  the  equation  and  calculate  how  much 
permanganate  would  be  necessary  to  oxidize  5  grams  of 
crystallized  oxalic  acid. 

Save  a  specimen  of  oxalic  acid.  Write  out  equations 
after  glucose  has  been  considered. 

1  Since  the  action  may  be  quite  violent,  it  is  best  to  put  the  sugar 
into  the  flask  and  damp  the  flask  under  the  hood  exhaust  before  the 
acid  is  added. 

72 


EXPERIMENT  32 
BASIC  FERRIC   SUCCINATE 

Dissolve  about  a  gram  of  succinic  acid  in  water,  and 
neutralize  carefully  with  dilute  ammonia  solution.  Add 
some  of  this  solution  of  ammonium  succinate  to  a  neutral 
solution  of  manganese  chloride  and  ferric  chloride,  and 
boil.  A  precipitate  is  formed.  What  is  it?  Filter  it  off, 
and  test  the  nitrate  for  iron  and  for  manganese,  and 
draw  your  own  conclusions  from  the  results.  Has  the 
nitrate  an  acid  reaction?  Explain.  Compare  results  with 
those  obtained  in  Experiment  19. 

EXPERIMENT  33 
FEHLING'S  SOLUTION 

Dissolve  3.5  grams  of  crystallized  copper  sulphate  in 
50  cc.  of  distilled  water.  Bottle  and  label,  "Copper 
Sulphate  Solution."  Dissolve  17.3  grams  of  Rochelle  salt 
and  10  grams  of  anhydrous  sodium  carbonate  in  50  cc.  of 
water.  Bottle  and  label,  "Alkaline  Tartrate  Solution." 
For  use  mix  equal  volumes  of  the  two  solutions  and  dilute 
with  an  equal  volume  of  distilled  water. 

Into  a  small  porcelain  dish  put  5  cc.  of  each  of  the ' 
above  solutions  and  add  10  cc.  of  distilled  water.  Heat 
nearly  to  boiling  and  add  a  few  drops  of  a  1%  solution  of 
glucose.  Note  what  takes  place.  Continue  to  add  the 
glucose  solution  drop  by  drop  until  the  precipitate  settles 
and  leaves  the  solution  clear  and  colorless.  Filter  off 
the  precipitate,  wash  with  hot  water,  dry,  and  save 
specimen.  What  is  this  precipitate?  What  becomes  of 
the  glucose?  Does  a  solution  of  glucose  reduce  an  am- 
moniacal  solution  of  silver  oxide?  Try  it.  What  con- 
clusions do  you  draw  from  these  facts  as  to  the  constitu- 
tion of  glucose? 

74 


EXPERIMENT  34 
PHENYLGLUCOSAZONE » 

Put  1  gram  of  pure  glucose,  2  grams  of  pure  phenyl 
hydrazine  hydrochloride,  3  grams  of  crystallized  sodium 
acetate  and  20  cc.  of  distilled  water  in  a  small  round 
bottom  flask.  Close  the  flask  loosely  with  a  cork  to  pre- 
vent evaporation  and  place  it  in  a  beaker  half  full  of 
boiling  water.  Note  the  time  that  the  flask  is  placed  in 
the  boiling  water.  Shake  the  flask  occasionally,  without 
removing  it  from  the  hot  water,  and  note  the  time  that 
elapses  before  the  appearance  of  a  precipitate.  What 
color  has  the  precipitate?  Filter  off  the  precipitate,  wash 
with  cold  water  and  recrystallize  from  50%  alcohol. 
Determine  the  melting  point  of  the  osazone,  heating  the 
sulphuric  acid  in  the  Thiele  tube  rapidly. 

Repeat  the  experiment,  using  fructose  instead  of  glucose, 
noting  the  time  that  elapses  between  the  immersion  of 
the  flask  in  the  boiling  water  and  the  appearance  of  the 
precipitate.  What  color  has  the  precipitate?  Recrystal- 
lize the  precipitate  from  50%  alcohol  and  determine  its 
melting  point.  Is  the  osazone  thus  obtained  identical 
with  that  made  from  glucose?  Explain. 

1See  Mulliken's  Identification  of  Pure  Organic  Compounds,  vol.  I, 
pp.  30, 32. 


76 


EXPERIMENT  35 
HYDROLYSIS   OF   SUCROSE 

Dissolve  1.5  grams  of  cane  sugar  in  200  cc.  of  distilled 
water.  Test  a  little  of  this  solution  with  the  Fehling's 
solution,  proceeding  as  directed  in  Experiment  33.  Does 
any  reduction  of  the  copper  solution  take  place?  Now 
add  to  the  sugar  solution  about  ten  drops  of  cone,  hydro- 
chloric acid  and  heat  the  mixture  on  the  water  bath  to  100° 
for  half  an  hour.  Neutralize  the  solution  exactly  with  a 
dilute  solution  of  sodium  carbonate,  and  again  test  it 
with  Fehling's  solution.  Does  any  reduction  take  place 
now?  What  is  the  function  of  the  hydrochloric  acid? 
Explain. 

Given  a  solution  containing  both  cane  sugar  and  glu- 
cose, show  how  you  could  estimate  both  by  means  of 
Fehling's  solution. 

EXPERIMENT  36 
CELLULOSE 

Obtain  some  pure  cellulose l  from  the  assistant.  Has  cel- 
lulose any  crystalline  form?  Try  dissolving  it  in  the  or- 
dinary solvents  and  record  your  results.  Dissolve  some 
in  a  small  quantity  of  cone,  sulphuric  acid  and  allow  the 
solution  to  stand  for  some  time.  Dilute  with  a  large 
volume  of  water  and  boil  the  solution  for  a  half  hour. 
Neutralize  exactly  with  an  alkali  and  test  with  Fehling's 
solution.  Does  any  reduction  take  place?  Does  the 
original  cellulose  reduce  Fehling's  solution?  Explain. 

1  Absorbent  cotton  or  pure  filter  paper  will  do.  How  are  they  made? 


78 


EXPERIMENT  37 
CELLULOSE  ACETATE 

Put  20  cc.  of  glacial  acetic  acid,  6  cc.  of  acetic  anhydride 
and  2  drops  of  cone.  C.  P.  sulphuric  acid  in  a  small  glass 
stoppered  bottle.  Shred  into  small  pieces  0.5  gram  of  ab- 
sorbent cotton  and  stir  this  thoroughly  into  the  above 
solution.  Stopper  and  let  the  mixture  stand  for  several 
days  or  until  a  clear  solution  is  obtained.  Then  pour 
this  clear  solution  slowly  into  a  beaker  containing  500  cc. 
of  water  with  vigorous  stirring.  Filter  on  a  Buchner 
funnel  and  dry  by  pressing  the  mass  between  pieces  of 
drying  paper.  What  is  it?  Save  a  small  specimen. 

Allow  about  one  half  of  the  product  to  stand.in  a  small 
Erlenmeyer  flask  with  20  cc.  of  chloroform  until  it  has 
completely  dissolved.  Then  pour  this  clear  solution  upon 
a  large  watch  glass  and  allow  the  chloroform  to  slowly 
evaporate.  Then  pour  cold  water  over  the  film  (?)  and 
allow  it  to  stand  for  a  few  minutes.  Lift  the  edge  of  the 
film  and  carefully  remove  it  from  the  glass.  Dry. 

Is  the  film  flammable?  For  what  purposes  is  it  used? 
Try  its  solubility  in  alcohol  and  ether. 


80 


EXPERIMENT  38 
SCHWEIZER'S  REAGENT 

(Ammoniacal  Solution  of  Copper  Oxide) 

To  a  mixture  of  100  cc.  of  a  cone,  solution  of  ammonia 
and  30  cc.  of  water  contained  in  a  250  cc.  glass  stoppered 
bottle  add  5  grams  of  copper  carbonate.  Shake  vigor- 
ously for  a  minute  or  two  and  then  allow  the  mixture  to 
stand  for  one  hour,  with  occasional  shaking.  If  a  residue 
remains,  decant  the  supernatant  liquid  or  filter  through 
glass  wool  and  use  the  solution  for  the  following  experi- 
ments. 

Does  the  above  solution  dissolve  cellulose?  Try  it 
with  some  cotton  cloth,  filter  paper  and  some  absorbent 
cotton.  Dilute  the  solutions  thus  obtained  with  water, 
filter  them  through  glass  wool  (?),  and  acidify  with 
dilute  hydrochloric  acid.  What  happens? 

Explain  the  Willesden  process  for  waterproofing  cot- 
ton fabrics.1  What  is  "Glanzstoff  "? 

1See  Thorpe's  Dictionary  of  Applied  Chemistry,  under  Cellulose. 


82 


EXPERIMENT  39 
STARCH 

Grind  in  a  small  mortar  a  gram  of  arrowroot  starch 
with  some  distilled  water.  Pour  the  creamy  mass  thus 
produced  slowly  into  500  cc.  of  boiling  distilled  water 
contained  in  a  porcelain  dish,  stirring  constantly  while 
the  starch  is  being  added  so  as  to  avoid  the  formation 
of  lumps.  A  few  drops  of  this  solution  is  then  added  to 
a  liter  of  water  and  one  drop  of  a  solution  of  potassium 
iodide.  Does  any  color  appear?  Add  a  drop  or  two  of 
freshly  prepared  (?)  chlorine  water  and  note  what  takes 
place.  Explain.  Is  the  color  destroyed  when  chlorine 
water  is  added  in  excess?  when  alkalies  are  added?  by 
sulphurous  acid?  by  hydrogen  sulphide?  by  sodium  thio- 
sulphate?  Try  it  with  each  reagent  with  a  small  quan- 
tity in  a  test  tube.  Explain  and  write  out  all  equations. 
Does  the.  color  disappear  on  heating?  Heat  some  in  a 
test  tube,  and  then  cool.  Does  the  color  reappear  on 
cooling?  Explain.  From  the  above  conduct  state 
whether  the  starch-iodine  compound  is  a  chemical  com- 
pound or  not.  Test  the  delicacy  of  this  reaction  for 
iodine  and  for  starch. 


EXPERIMENT  40  \ 

HYDROLYSIS  OF  STARCH 

Test  some  of  the  starch  paste  solution  made  in  Ex- 
periment 39  with  Fehling's  solution.  Does  it  reduce  it? 
Add  5  cc.  of  concentrated  hydrochloric  acid  to  200  cc.  of  the 
starch  paste  solution,  and  heat  to  boiling  in  a  flask  con- 
nected with  a  condenser  for  an  hour  and  a  half.  When 
cold,  neutralize  with  sodium  carbonate  solution,  and 
examine  with  Fehling's  solution.  Does  it  reduce  the 
Fehling's  solution  now?  Does  the  solution  now  contain 
any  starch?  Test  it  with  a  solution  of  iodine  in  potas- 
sium iodide  solution.  Explain. 
84 


EXPERIMENT  41 
ETHYL  FORMATE,  DEETHYL  OXALATE  AND  OXAMIDE 

Grind  100  grams  of  crystallized  oxalic  acid  to  powder, 
and  dehydrate  by  heating  in  an  air  bath  to  100°.  Weigh 
the  anhy&ous  oxalic  acid,  and  add  to  it  an  equal  weight 
of  absolute  alcohol.  Boil  this  mixture  in  a  flask  con- 
nected with  a  reflux  condenser  for  four  hours.  Then 
transfer  to  a  distilling  flask,  and  distil  until  the  temper- 
ature reaches  110°.  Add  to  the  residue  left  in  the  dis- 
tilling flask  a  volume  of  absolute  alcohol  equal  to  that  of 
the  distillate,  and  again  boil  for  four  hours  in  the  ap- 
paratus first  used.  Once  more  transfer  to  the  distilling 
flask,  and  distil.  When  the  temperature  reaches  145°, 
change  the  receiver,  increase  the  heat,  and  distil  off  the 
residue  as  quickly  as  possible.  From  the  first  fractions 
separate  the  ethyl  formate,  by  fractional  distillation, 
using  a  Hempel  distilling  tube,  and,  from  the  second,  the 


boiling  point,  color,  taste,  odor,  specific 
id  flam  in  ability  of  both  substances,  and  explain 
iheir  formation. 

To  the  alcoholic  solution  of  diethyl  oxalate,  resulting 
from  the  fractionation,  add  some  concentrated  ammonia 
solution.  What  takes  place?  Filter  off  the  precipitate, 
wash,  and  ermine.  Boil  some  with  a  little  caustic  soda 
solution  in  a  test  tube.  Does  it  dissolve?  What  gas 
comes  off?  What  remains  in  solution?  Prove  it. 

Save  specimens  of  ethyl  formate^  diethyl  oxalate,  and 
oxamide. 


EXPERIMENT  42 
UREA 

Dissolve  20  grams  of  the  potassium  cyanate,  obtained 
as  directed  in  Experiment  26,  in  cold  (?)  water  and  add 
to  it  a  solution  of  ammonium  sulphate,  containing  the 
calculated  amount  of  ammonium  sulphate  to  change  the 
potassium  cyanate  to  potassium  sulphate.  Evaporate 
the  solution  to  dryness  on  the  water  bath,  and  extract 
the  residue  with  boiling  absolute  alcohol.  Filter  and 
evaporate  to  crystallization.  Determine  crystal  form, 
melting  point,  solubility,  color,  taste,  odor,  etc.  Heat  a 
little  of  the  dry  substance.  What  is  formed?  Treat  a 
concentrated  solution  in  a  test  tube  with  a  solution  of 
oxalic  acid,  and  explain  what  takes  place.  Add  a  dilute 
solution  of  urea  to  a  dilute  solution  of  mercuric  nitrate. 
What  takes  place?  Add  a  little  mercuric  oxide  to  a  so- 
lution of  urea.  What  takes  place? 

Dissolve  8  grams  of  caustic  soda  in  100  cc.  water,  and 
bromine.  What  does  this  solution  contain? 
Dlution  of  urea,  and  add  to  some  of  the  above 

^^^^  gas  is  given  off.  Collect  some,  and  de- 
termine what  it  is.  What  remains  in  solution?  Urea 
may  be  determined  in  urine  by  this  method.  How  is 
urea  determined  in  the  urine  at  the  present  time? 

Dissolve  a  small  quantity  of  sodium  nitrite  in  water, 
and  add  to  it  an  acidified  solution  of  urea.  What  takes 
place?  Explain. 

What  is  formed  when  ammonium  thiocyanate  is  heated 
to  its  melting  point? 

Save  a  specimen  of  the  urea. 


EXPERIMENT  43 
ETHYLENE  AND  ETHYLENE  BROMIDE 

Put  200  cc.  cone,  sulphuric  acid,  100  cc.  95%  alcohol 
and  10  grams  of  anhydrous  aluminum  sulphate1  in  a  500 
cc.  distilling  flask.  Close  the  flask  with  a  cork  carrying 
a  thermometer  the  bulb  of  which  dips  below  the  surface 
of  the  liquid.  Connect  the  flask  with  3  Muencke  gas 
washing  bottles,  the  first  containing  water,  the  second 
10  cc.  of  bromine2  and  20  cc.  of  water  and  the  third  water 
only.  Heat  the  flask  to  138°-145°.  What  gas  comes 
off?  When  the  bromine  has  been  decolorized  (explain), 
separate  the  ethylene  bromide  from  the  water,  using  a 
separatory  funnel,  wash  with  dilute  caustic  soda  solution, 
then  with  water,  again  separate  from  the  water,  dry  with 
calcium  chloride  and  distil,  noting  the  boiling  point. 

Determine  its  color,  taste,  specific  gravity  (lighter  or 
heavier  than  water),  odor  and  solubility.  Does  it  solidify 
on  cooling?  What  is  formed  when  it  is  treated  in  alco- 
holic solution  with  granulated  zinc?  How  is  ethylene 
alcohol  (glycol)  made  from  ethylene?  Save  a  specimen 
of  ethylene  bromide. 

1  Made  by  calcinining  ammonium  alum. 

1  Bromine  should  always  be  handled  very  carefully  and  under  the  hood. 


90 


EXPERIMENT  44 
ALLYL  ALCOHOL  AND  ACROLEIN 

(Hood) 

Put  200  grams  glycerol  and  70  grams  of  85%  formic 
acid  in  a  500  cc.  distilling  flask  connected  with  a  conden- 
ser, adapter  and  a  suction  flask  as  a  receiver.  Close  the 
distilling  flask  with  a  cork  carrying  a  thermometer,  the 
bulb  of  which  is  immersed  in  the  liquid.  The  side  tube 
of  the  suction  flask  is  connected  with  a  gas  washing  bot- 
tle containing  30  cc.  of  water  and  surrounded  with  crushed 
ice.  Heat  the  distilling  flask  (which  is  provided  with 
an  ebullator  tube  to  prevent  bumping)  rapidly.  The 
distillate  up  to  195°  is  collected  separately  and  the  heat- 
ing is  continued  until  the  cemperature  reaches  260°,  when 
it  is  stopped.  The  distillate  between  195°-260°  is  saved. 
Allow  the  contents  of  the  distilling  flask  to  cool  to  100° 
and  then  add  70  grams  more  of  the  85%  formic 
acid  and  repeat  the  distillation  in  the  same  manner  as 
described  above.  The  combined  distillates  (195°-260°) 
are  treated  with  solid  potassium  carbonate,  the  allyl  al- 
cohol separated  from  the  solution  of  potassium  carbonate 
and  distilled,  collecting  the  distillate  up  to  103°.  Heat 
this  distillate  with  several  grams  of  solid  potassium  car- 
bonate, using  a  reflux  condenser  and  separate  the  car- 
bonate solution  from  the  alcohol.  Repeat  this  procedure 
until  a  fresh  portion  of  the  carbonate  takes  up  no  more 
water.  Separate  the  alcohol  from  the  carbonate  and  distil 
it,  noting  the  boiling  point. 

Determine  the  odor,  taste  and  solubility.  Does  it 
decolorize  bromine  water?  Explain.  Does  it  decolorize 
a  dilute  solution  of  potassium  permanganate?  Explain. 
Is  allyl  alcohol  a  primary  alcohol?  Save  a  specimen  of 
the  allyl  alcohol. 

92 


Examine  the  water  in  the  gas  washing  bottle.  Note 
the  odor.  To  what  is  it  due?  Does  the  solution  reduce 
an  ammoniacal  solution  of  silver  oxide?  Prepare  a  silver 
mirror  according  to  the  directions  given  in  Experiment  16. 
Save  the  mirror. 

Does  the  solution  decolorize  bromine  water?  Does  it 
decolorize  a  dilute  solution  of  potassium  permanganate? 
Explain. 

EXPERIMENT  45 
ACETYLENE 

(Hood) 

Put  5  grams  of  calcium  carbide  in  a  dry  500  cc.  suction 
flask  provided  with  a  separatory  funnel.  The  side  tube 
of  the  suction  flask  is  connected  with  a  wide  delivery 
tube  and  water  is  added  through  the  separatory  funnel 
drop  by  drop.  Collect  some  of  the  gas  in  a  test  tube  over 
water  and  see  if  it  burns. 

Pass  some  of  the  gas  through  a  dilute  solution  of  po- 
tassium permanganate  contained  in  a  test  tube  and  note 
what  happens.  Explain.  Pass  some  of  the  gas  through 
an  alcoholic  solution  of  iodine  in  a  test  tube.  What 
takes  place?  Explain.  Show  how  acetic  aldehyde,  acetic 
acid,  and  ethyl  alcohol  could  be  acetylene. 

Prepare  10  cc.  of  an  ammoniacal  solution  of  silver 
oxide  (see  Experiment  16)  and  pass  the  gas  through  it 
until  the  reaction  is  complete.  A  precipitate  is  formed. 
What  is  it?  Filter  it  off,  wash  with  water  and  examine. 
Determine  color  and  solubility.  Does  it  resemble  silver 
chloride  in  any  respect?  Explain.  Does  it  explode  when 
heated  or  on  percussion?  Dry  some  carefully  and  try  it. 
Save  any  silver  solutions  and  put  into  bottle  marked 
"  Silver  Residues,"  Destroy  all  of  the  silver  of  salt  (?). 


94 


EXPERIMENT  46 
BENZENE 

Grind  together  intimately  in  a  mortar  50  grams  of 
benzoic  acid  and  100  grams  of  good  soda-lime.  Put  the 
mixture  in  an  iron  retort,  using  an  asbestos  paper  gasket. 
Connect  the  delivery  tube  of  the  retort  with  an  adapter, 
and  surround  the  receiver  with  ice  water.  Heat  the  re- 
tort with  a  triple  burner,  and  continue  the  heating  until 
liquid  ceases  to  distil.  Separate  the  oil  from  the  water 
in  the  distillate,  wash  with  dilute  caustic  soda  solution  (?), 
dry  with  fused  calcium  chloride,  as  usual,  and  redistil 
from  a .  small  distilling  .flask,  noting  the  temperature  at 
which  it  boils.  What  is  the  substance  thus  obtained? 

Determine  its  specific  gravity  (lighter  or  heavier  than 
water),  odor,  color,  taste  and  flammability.  'Does  it 
solidify  when  cooled  to  0°?  Try  it.  Is  it  a  good  solvent? 
Try  it.  What  remains  in  the  retort  in  which  this  sub- 
stance was  made?  Is  there  any  analogy  between  this 
method  of  making  benzene  and  the  method  of  making 
marsh  gas?  Save  a  specimen  of  the  benzene. 


96 


EXPERIMENT  47 
NITROBENZENE » 

(Hood} 

A  cooled  mixture  of  60  grams  of  concentrated  nitric 
acid  and  80  grams  of  ordinary  concentrated  sulphuric 
acid  is  slowly  and  carefully  added  from  a  separatory  fun- 
nel drop  by  drop,  and  with  constant  shaking,  to  50  grams 
of  benzene,  contained  in  a  ^  liter  flask,  care  being  taken 
to  prevent  the  temperature  rising  above  50°.  Gases 
come  off.  What  are  they?  Explain.  When  all  the  acid 
has  been  added,  heat  the  mixture  on  a  boiling  water  or 
steam  bath  for  half  an  hour,  shaking  the  flask  constantly. 
After  cooling,  pour  the  mixture  into  half  a  liter  of  cold 
water,  and  separate  the  acid  layer  by  means  of  a  sepa- 
ratory funnel.  Wash  the  oil  remaining  several  times 
with  water,  and  then  with  dilute  soda  solution,  drawing 
off  the  oil  each  time  from  the  bottom  of  the  funnel.  Wash 
finally  with  water,  separate  the  oil  from  the  water  as 
completely  as  possible,  dry  with  calcium  chloride  in  the 
usual  way,  and  subject  to  distillation,  using  a  plain  tube 
as  a  condenser  and  noting  the  boiling  point.  What  comes 
over?  What  is  the  brownish  residue  left  in  the  flask? 
Determine  the  specific  gravity,  solubility,  color,  taste  and 
odor.  Does  it  solidify  on  cooling?  Why  is  the  sulphuric 
acid  added  in  the  preparation  of  the  nitrobenzene? 

Save  a  small  specimen  of  the  substance,  and  use  the  rest 
in  the  following  experiment. 

irThe  vapor  of  nitrobenzene  is  poisonous,  and  care  should  be  taken 
not  to  inhale  it. 


EXPERIMENT  48 
DINITROBENZENE 

(Hood) 

15  grams  of  nitrobenzene  are  gradually  added  from  a 
separatory  funnel  to  a  mixture  of  25  grams  of  concentrated 
nitric  acid  and  40  grams  of  concentrated  sulphuric  acid, 
contained  in  a  flask  of  500  cc.  capacity.  The  flask 
should  not  be  cooled,  but  should  be  frequently  shaken 
during  the  addition  of  the  nitrobenzene.  When  all 
the  nitrobenzene  has  been  added,  heat  the  flask  gently 
until  red  fumes  cease  to  be  given  off  and  the  reaction  is 
complete.  The  flask  should  be  shaken  constantly  dur- 
ing the  heating.  After  cooling,  pour  slowly  into  a  liter 
of  water.  Filter  off  the  crystals  on  a  Buchner  funnel, 
using  a  suction  pump  to  drain  thoroughly,  wash  free  from 
acid,  drain,  and  recrystallize  from  hot  alcohol. 

Determine  the  melting  point,  crystal  form,  solubility, 
color,  odor  and  taste  of  the  crystals.  What  substances 
remain  in  the  alcoholic  mother  liquor?  Save  a  specimen 
of  the  crystals. 


100 


EXPERIMENT  49 
ANILINE 

Put  150  cc.  of  water,  55  grams  of  finely  divided  cast  iron 
filings,  and  40  grams  of  nitrobenzene  into  a  1500  cc. 
round  bottom  flask  connected  with  a  reflux  condenser. 
Add  20  grams  of  concentrated  hydrochloric  acid  through 
the  inner  tube  of  the  condenser.  Heat  gently  with  a 
small  flame  until  the  reaction  begins.  After  "the  first 
•violent  reaction  is  over,  heat  the  contents  of  the  flask  to 
boiling  and  continue  until  the  odor  of  nitrobenzene  has 
disappeared  (about  10  hours).  Then  add  water  (250  cc.) 
to  the  flask,  and  distil  with  steam.  //  the  distillate  has 
the  odor  of  nitrobenzene  and  a  little  of  the  oil  is  not 
completely  soluble  in  cone,  hydrochloric  acid,  add  cone, 
hydrochloric  acid  until  the  aniline  has  entirely  dissolved 
and  extract  the  nitrobenzene  by  shaking  with  ether. 
Then  remove  the  ether,  concentrate  the  aqueous  solution, 
and  add  caustic  soda  solution  to  alkaline  reaction,  put 
into  a  separatory  funnel,  and  extract  two  or  three  times 
with  small  quantities  of  ether.  If  the  distillate  does  not 
smell  of  nitrobenzene,  and  a  little  of  the  oil  dissolves  com- 
pletely in  hydrochloric  acid,  simply  extract  it  once  or 
twice  with  etfcer.  Separate  the  ether  extracts  from  the 
water  as  completely  as  possible,  dry  with  solid  caustic 
soda,  place  in  a  distilling  flask,  and  distil  off  the  ether 
(with  care}.  Finally,  increase  the  heat,  and  distil  the 
aniline.  Determine  its  boiling  point,  solubility,  specific 
gravity  (lighter  or  heavier  than  water),  color,  odor,  and 
taste.  Has  the  solution  in  water  an  alkaline  reaction? 
Try  it.  Does  aniline  dissolve  in  dilute  acids?  Explain. 
Is  it  affected  by  the  light?  Does  its  aqueous  solution 
precipitate  salts  of  zinc,  aluminum,  and  iron?  Try  it. 
102 


Explain.  Does  aniline  decompose  ammonium  salts?  Heat 
some  with  ammonium  chloride.  Is  ammonia  given  off? 

Save  a  small  specimen  of  aniline. 

To  a  dilute  aqueous  solution  of  some  of  the  aniline  add 
an  excess  of  a  filtered  solution  of  bleaching-powder,  and 
note  the  result.  Explain.  Very  dilute  solutions  of  ani- 
line give  but  a  slight  coloration,  but  a  color  is  brought  out 
by  adding  a  few  drops  of  a  dilute  solution  of  ammonium 
sulphide  to  the  mixture.  Try  it,  and  test  the  delicacy  of 
this  last  reaction. 

To  a  solution  of  aniline  in  concentrated  sulphuric  acid 
add  a  few  grains  of  solid  potassium  bichromate,  and  warm 
the  test  tube  gently.  What  takes  place? 

EXPERIMENT  50 

PHENYL  ISO  CYANIDE 
(Hood} 

Dissolve  a  small  quantity  of  solid  caustic  potash  in 
alcohol  in  a  test  tube  and  add  one  or  two  drops  of  aniline. 
Then  add  a  drop  of  chloroform  to  100  cc.  of  distilled 
water  in  a  small  flask,  and  shake  the  mixture  thoroughly. 
Now  add  a  drop  or  two  of  this  water  saturated  with 
chloroform  to  the  caustic  potash  solution  containing  the 
aniline,  and  heat  the  test  tube  under  the  hood.  The  odor 
is  that  of  phenyl  isocyanide. 

This  reaction  is  a  very  delicate  one,  and  may  be  used 
to  detect  the  presence  of  any  primary  amine  or  of  chloro- 
form. Is  aniline  an  amine?  What  is  the  object  of  the 
caustic  potash? 


104 


EXPERIMENT  51 
m-NITROANILINE 

Dissolve  5  grams  of  pure  dinitrobenzene  in  20  grams  of 
alcohol  in  a  250  cc.  Erlenmeyer  flask.  The  solution  is 
cooled;  a  portion  of  the  dinitrobenzene  separates.  Then 
add  4  grams  of  cone,  ammonia  solution.  The  flask  is 
then  weighed,  the  weight  noted  and  the  mixture  saturated 
with  hydrogen  sulphide  (Hood),  at  room  temperature. 
The  flask  is  then  connected  with  a  reflux  condenser  and 
the  solution  heated  on  a  water  bath  for  a  half  hour.  Cool, 
saturate  again  with  hydrogen  sulphide  and  then  reflux  as 
before.  Continue  this  operation  until  there  has  been  3 
grams  increase  in  weight.  The  mixture  is  then  diluted 
with  water,  the  precipitate  is  filtered  off  and  washed  with 
water.  It  is  then  extracted  several  times  with  warm, 
dilute  hydrochloric  acid  and  the  solution  filtered.  The 
nitroaniline  is  set  free  from  the  combined  acid  filtrates  by 
neutralizing  with  ammonium  hydroxide  and  recrystallized 
from  hot  water. 

Determine  melting  point  and  color. 

How  is  this  substance  made  on  the  large  scale?  How 
could  both  nitro  groups  in  dinitrobenzene  be  reduced? 
What  is  the  product  called? 


106 


EXPERIMENT  52 
ACETANILIDE 

(Hood) 

To  5  cc.  of  aniline  add  acetyl  chloride  (about  5  cc.), 
drop  by  drop,  through  a  small  separatory  funnel,  waiting 
between  each  drop  until  the  vigorous  action  ceases. 
When  no  action  takes  place  upon  the  addition  of  a  drop 
of  the  acetyl  chloride  the  reaction  is  complete.  Pour 
the  mixture  into  five  times  its  volume  of  water,  shake  and 
allow  it  to  stand  for  a  few  minutes.  What  is  the  solid 
which  separates?  Recrystallize  it  from  hot  water  and  de- 
termine its  melting  point.  What  does  it  give  when 
hydrolyzed  with  solutions  of  the  alkalies? 

For  what  purpose  is  acetanilide  used?  What  effect 
has  the  introduction  of  the  acetyl  group  into  the  auiline 
molecules  on  the  toxicity? 


EXPERIMENT  53 
BENZENE  DIAZONIUM   CHLORIDE 

Suspend  10  grams  of  powdered  aniline  hydrochloride  in 
30  grams  of  glacial  acetic  acid  and  15  cc.  of  absolute 
alcohol,  cool  below  8°  and  add,  with  constant  shaking  and 
slowly,  10  grams  of  amyl  nitrite,1  taking  care  that  the 
temperature  does  not  rise  above  8°.  The  suspended  ani- 
line hydrochloride  quickly  dissolves  and  the  diazotization 
is  complete  when  a  small  portion  of  the  mixture,  removed 
with  a  pipette,  no  longer  gives  a  yellow  color  when  treated 
with  a  solution  of  sodium  acetate  (?).  Then  treat  with 
an  equal  volume  of  ether,  keeping  the  temperature  be- 
low 0°.  Filter  off  the  crystals  of  the  diazonium  chloride 

1  Do  not  breathe  the  vapor  of  amyl  nitrite. 


108 


on  a  Buchner  funnel  by  suction,  wash  with  a  little  ether, 
and  dry  in  the  air  on  drying  paper.1  - 

Determine  the  color,  solubility,  and  crystal  form  of  the 
salt.  Does  it  decompose  on  standing  in  the  light?  Does 
it  act  like  a  substituted  ammonium  salt  towards  solutions 
of  platinum  chloride  and  gold  chloride?  Does  it  give  a 
perbromide  with  a  solution  of  bromine  in  potassium  bro- 
mide? Does  NHJSr  form  a  perbromide? 

(a)  Heat  some  of  the  dry  salt  cautiously  on  platinum 
foil,  and  note  what  takes  place.  Does  the  salt  explode  on 
percussion?  Try  it 

(6)  Boil  some  with  absolute  alcohol,  and  describe  what 
takes  place.  What  are  the  products  of  the  reaction? 

(c)  Boil  a  little  of  the  dry  salt  with  water.     What 
takes  place?    What  are  the  products  of  the  reaction? 
Prove  it. 

(d)  Treat  a  cold  solution  of  dimethylaniline  in  water 
with  a  cold  aqueous  solution  of  benzene  diazonium  chlo- 
ride and  observe  what  takes  place.      Explain. 

(e)  Treat  a  cold  solution  of  phenol  in  water  with  a  cold 
aqueous  solution  of  benzene  diazonium  chloride  and  make 
the  solution  alkaline  with  sodium  carbonate  solution  and 
note  what  takes  place.     Explain. 


1  The  dry  salt  is  very  explosive,  and  great  care  must  be  exercised  in 
handling  it.  Perform  the  whole  experiment  in  one  period  and  wash 
out  all  vessels  containing  the  salt  at  once  with  water  and  use  up  all 
of  the  material  before  leaving  the  laboratory. 


110 


EXPERIMENT  54 

IODOBENZENE,    IODOBENZENE    BICHLORIDE,    AND 
IODOSOBENZENE 

Dissolve  10  grams  of  freshly  distilled  aniline  in  a  mix- 
ture of  50  grams  cone,  hydrochloric  acid  and  150  cc.  of 
water  in  a  500  cc.  Erlenmeyer  flask.  Cool  the  mixture 
with  ice  water, below  8°  and  add  gradually,  with  constant 
shaking,  a  cold  solution  of  9  grams  of  sodium  nitrite  in 
50  cc.  of  water,  until  an  excess  of  nitrous  acid  is  shown  to 
be  present  by  the  blue  color  a  drop  of  the  solution  imparts 
to  starch-potassium-iodide  paper.  Explain.  What  does 
this  solution  now  contain?  When  the  diazotization  is  com- 
pkte  (?)  transfer  the  solution  to  a  2  liter  balloon  flask, 
cool  to  8°  and  add  a  solution  of  18  grams  of  potassium 
iodide  in  40  cc.  of  water  and  allow  the  mixture  to  stand 
for  about  2  hours  at  about  8°.  Then  heat  it  gently  on 
the  water  or  steam  bath  until  the  evolution  of  nitrogen 
ceases.  Explain  what  takes  place.  Make  the  liquid 
strongly  alkaline  with  caustic  soda  solution  (?),  distil  off 
the  oil  with  steam,  separate  it  from  the  water  by  means 
of  a  separately  funnel,  dry  with  calcium  chloride,  and 
redistil  it,  noting  the  boiling  point.  What  is  the  substance 
thus  obtained?  Determine  the  color,  odor,  action  of 
light,  solubility  and  specific  gravity  (lighter  or  heavier 
than  water)  of  the  liquid.  Save  a  specimen. 

Dissolve  some  of  the  iodobenzene  in  five  times  its 
volume  of  chloroform,  and  saturate  the  solution  with  dry 
chlorine,  using  a  wide  delivery  tube  and  keeping  the  solu- 
tion cold  by  surrounding  it  with  a  freezing  mixture. 
Filter  off  the  crystals  formed  and  dry  them  in  the  air  on 
drying  paper.  Save  a  small  specimen.  What  is  this 
compound?  Does  iodine  have  basic  properties? 

Triturate  the  rest  of  the  crystals  obtained  above  with  a 
dilute  solution  of  caustic  soda  (for  each  gram  of  the 
crystals,  use  0.5  gram  sodium  hydroxide  in  4  grams  of 
water)  and  allow  the  mixture  to  stand  over  night.  Filter 
off  the  crystals,  wash  with  water  and  dry  on  drying  paper. 
112 


Save  a  specimen.     What  is  this  product?    Does  it  have 
basic  properties? 

The  filtrate  is  then  treated  with  sulphur  dioxide  until  it  is 
saturated  with  the  gas  and  smells  strongly  of  it.  The  pre- 
cipitate formed  is  filtered  off  and  recrystallized  from  boiling 
water.  Save  a  specimen.  What  is  the  product?  Explain  its 
formation.1 

EXPERIMENT  55 
BENZENE   SULPHONIC  ACID2 

Place  300  grams  of  fuming  sulphuric  acid  (containing 
.  20%  SO3)  in  a  500  cc.  flask  and  add  gradually,  by  means 
of  a  separatory  funnel  and  with  constant  shaking  and 
thorough  cooling  with  ice  water  100  grams  of  benzene. 
Before  adding  each  new  quantity  of  the  benzene,  see  that 
the  last  portion,  which  at  first  floats  on  the  surface  of  the 
acid,  dissolves  on  shaking,  and  keep  the  temperature  of  the 
add  below  50°  (?).  When  all  the  benzene  has  dissolved, 
Which  will  require  about  15  minutes,  cool  the  mixture  to  0°, 
place  it  in  a  separatory  funnel  and  add  it,  gradually  and 
with  constant  stirring,  to  a  solution  of  200  grams  of  sodium 
chloride  in  800  cc.  of  water.  The  sodium  chloride  solu- 
tion is  kept  at  0°  by  surrounding  it  with  ice  water.  The 
sodium  salt  of  benzene  sulphonic  acid  separates  at  once  or, 
on  the  addition  of  a  few  crystals  and  thorough  stirring,  in 
the  form  of  lustrous  leaflets.  After  allowing  the  mixture 
to  stand  for  some  time  at  0°,  filter  off  the  crystals  on  a 
Buchner  funnel  by  suction  and  drain  off  the  mother  liquor 
thoroughly.  Cool  the  filtrate  to  0°  again  as  another  crop 
of  crystals  may  be  obtained.  Dry  the  sodium  salt  in  a 
porcelain  dish  in  an  air-bath  at  110°.  Recrystallize  it 
from  95%  alcohol  and  dry  in  the  air  on  drying  paper. 
Save  a  specimen  of  the  crystallized  salt  and  determine  its 

1  See  Gatterman's  Practical  Methods  of  Organic  Chemistry,  trans,  by 
Schober  and  Babasinian,  3d  ed.,  1916,  p.  246. 

2  Great  care  must  be  used  in  handling  fuming  sulphuric  acid.     Di- 
rections should  be  followed  very  carefully,  as  enough  sodium  benzene 
sulphonate  must  be  made  for  the  following  experiments. 

114 


color,  crystal  form  and  solubility.  Does  it  contain  water 
of  crystallization?  Use  the  dry  salt  in  the  following  ex- 
periments. 

EXPERIMENT  56 

BENZENE   SULPHONYL   CHLORIDE  AND 
BENZENE   SULPHONAMIDE 

(Hood) 

Grind  together  in  a  porcelain  dish  equivalent  quantities 
(20  grams)  of  dry  sodium  benzene  sulphonate  (dried  at 
110°)  and  phosphorus  pentachloride  (24  grams).1  What 
is  formed?  Then,  after  cooling,  add  300  grams  of  ice  and 
water  with  stirring.  When  the  ice  has  melted  extract  the 
oil  with  300  cc.  of  ether.  Separate  the  ethereal  solution 
from  the  water,  dry  with  calcium  chloride  and  distil  off 
the  ether,  using  a  water  bath  and  observing  the  usual  pre- 
cautions. What  remains  in  the  distilling  flask?  Save  a 
small  specimen  and  to  the  rest  add  100  cc.  of  cone,  am- 
monia solution,  with  constant  stirring,  and  evaporate  to 
dryness  on  a  water  bath.  What  is  formed?  Recrystallize 
the  product  from  hot  water,  and  determine  its  melting 
point,  crystal  form,  solubility,  color,  taste  and  odor. 
Does  the  substance  dissolve  more  readily  in  ammonia  solu- 
tion than  in  water?  Explain.  Save  a  specimen. 

1  If  a  good  hood  is  not  available,  grind  the  materials  together  out 
of  doors. 


116 


EXPERIMENT  57 

PHENYL   CYANIDE    (BENZONITRILE)   AND  BENZOIC 
ACID 

(Hood} 

Grind  together  intimately  40  grams  of  crystallized 
sodium  benzene  sulphonate  and  12  grams  of  sodium  cy- 
anide, and  distil  the  mixture  from  an  iron  or  copper  re- 
tort, the  delivery  tube  of  which  is  connected  with  a  suc- 
tion flask  as  a  receiver  by  means  of  an  adapter.  What 
substance  distils?  Has  it  a  bad  pdor?  What  remains 
in  the  retort?  Prove  it.  Save  a  small  specimen  of  the 
oil.  How  is  phenyl  cyanide  made  from  aniline?  Com- 
pare the  odors  of  phenyl  cyanide  and  phenyl  isocyanide 
(Experiment  50).  Put  the  rest  of  the  oil  in  a  500  cc. 
flask,  add  150  cc.  of  strong  caustic  soda  solution,  connect 
the  flask  with  a  reflux  condenser,  and  boil  the  contents 
until  the  oil  disappears.  What  is  formed?  What  gas 
is  given  off?  After  cooling,  acidify  the  solution  with 
hydrochloric  acid.  Filter  off  the  precipitate  and  re- 
crystallize  it  from  hot  water.  Determine  its  melting 
point  and  properties  (see  Experiment  62).  Save  a 
specimen. 


118 


EXPERIMENT  58 
PHENOL  FROM   SODIUM   BENZENE   SULPHONATE1 

Dissolve  40  grams  of  sodium  benzene  sulphonate  in  as 
small  a  quantity  of  hot  water  as  possible  in  an  iron  cru- 
cible and  add  40  grams  of  solid  caustic  soda.  Heat  the 
crucible  with  a  flame  till  all  the  water  is  driven  off  and 
then  raise  the  temperature  to  325°-350°  and  continue 
the  heating  at  this  temperature  for  one  hour  with  con- 
stant stirring.  The  temperature  is  taken  with  a  ther- 
mometer fastened  by  means  of  a  cork  in  a  thin  iron  tube 
closed  at  one  end,  which  is  also  used  as  a  stirrer.  The 
hand  must  be  protected  by  a  glove  and  goggles  worn  dur- 
ing the  fusion.  When  cold  dissolve  the  fused  mass  in 
the  crucible  by  heating  with  several  portions  of  water. 
Acidify  the  solution  with  hydrochloric  acid.  What  gas 
is  given  off?  Extract  the  oil  with  several  portions  of 
ether,  dehydrate  the  ethereal  extract  with  potassium  car- 
bonate and  distil  off  the  ether,  observing  the  usual  pre- 
cautions. Then  increase  the  heat  and  distil  off  the  oil, 
noting  its  boiling  point.  Determine  odor,  color,  crystal 
form,  melting  point  and  solubility.  Save  a  specimen  and 
perform  the  experiments  (1,  2  and  3)  given  in  Experiment 
59. 

1  Do  not  allow  phenol  to  come  into  contact  with  the  skin.  It  pro- 
duces painful  and  serious  burns. 


120 


EXPERIMENT  59 
PHENOL  FROM  ANILINE 

Carefully  add  20  grams  of  cone,  sulphuric  acid  to  50 
grams  of  water.  While  still'  hot  add  10  grams  of  freshly 
distilled  aniline,  allowing  it  to  flow  down  the  sides  of  the 
beaker  slowly  while  stirring  the  solution  vigorously. 
Then  add  100  cc.  of  water.  Cool  by  surrounding  the 
beaker  with  a  freezing  mixture.  When  the  temperature 
is  about  0°,  add  slowly  and  with  constant  stirring  a  solu- 
tion of  9  grams  of  sodium  nitrite  in  50  cc.  of  water,  keeping 
the  temperature  below  8°  and  testing  for  excess  nitrous 
acid  with  starch-potassium-iodide  paper.  Let  the  mix- 
ture stand  until  the  diazotization  is  complete.  It  is  then 
gently  heated  for  a  half  hour  at  40°-50°  in  a  water  bath. 
What  gas  is  given  off ?  The  solution  is  then  subjected  to 
steam  distillation  until  all  the  phenol  has  distilled  over  (?). 
The  distillate  is  saturated  with  salt  and  extracted  several 
times  with  ether.  The  ethereal  extract  is  then  dried  with 
potassium  carbonate,  decanted  or  filtered  into  a  small, 
dry  distilling  flask  and  the  ether  distilled  off  with  the  usual 
precautions. 

What  remains  in  the  distilling  flask?  Save  a  small 
specimen.  Determine  odor,  color,  crystal  form,  boiling 
point  and  solubility.  Is  the  substance  poisonous?  What 
is  its  common  name?  Make  a  solution  of  it  in  water  and 
perform  the  following  experiments: 

1:  To  a  small  portion  of  the  solution  add  a  few  drops 
of  a  ferric  chloride  solution. 

2.  To  another  portion  of  the  solution  add  %  volume  of 
ammonia  solution,  and  then  a  few  drops  of  a  solution  of 
bleaching  powder  (1  part  to  20  of  water). 

3.  Add  a  few  drops  of  bromine  water  to  a  third  portion 
of  the  solution. 

Describe  what  takes  place  in  each  case. 
122 


EXPERIMENT  60 
ORTHO-  AND  PARA-NITROPHENOLS 

Carefully  dissolve  80  grams  of  sodium  nitrate  in  a 
mixture  of  100  grams  of  cone,  sulphuric  acid  and  200  cc. 
of  water.  Shake  well  and  cool  to  25°.  Add  through  a 
separately  funnel,  drop  by  drop,  with  constant  shaking, 
a  solution  of  50  grams  of  phenol l  in  5  grams  of  alcohoL 
When  all  the  phenol  has  been  added  shake  well  for  a  half 
an  hour  and  then  allow  the  solution  to  stand  for  2  hours. 
During  the  entire  procedure  the  temperature  of  the  solu- 
tion must  be  kept  as  near  25°  as  possible.  Then  add  two 
volumes  of  water;  a  heavy  reddish-brown  transparent  oil 
separates.  The  oil  is  separated  from  the  water  and  washed 
two  or  three  times  with  fresh  water.  The  oil  is  then  sub- 
jected to  steam  distillation  (cover  oil  with  water  until 
flask  is  half  full),  until  the  distillate  passes  over  almost 
colorless.  Filter  off  the  solid  (?)  in  the  receiver,  dry  and 
recrystallize  from  alcohol.  Save  a  small  specimen. 

Extract  the  oil  left  with  hot  water  several  times,  filtering 
the  aqueous  extract  while  hot.  On  cooling  the  filtrates 
crystals  separate  (?).  If  no  crystals  are  formed,  combine 
the  filtrates  and  concentrate  until  crystals  do  form  as  the 
solution  is  cooled.  If  the  crystals  are  yellow,  wash  with  a 
little  ice  water  (?),  until  colorless. 

Determine  the  crystal  form,  melting  point,  solubility, 
volatility,  color,  odor,  and  taste  of  both  substances.  Have 
they  acid  properties?  Explain. 

*Care  must  be  taken  in  handling  phenol. 


124 


EXPERIMENT  61 
PICRIC  ACID 

(Hood) 

Heat  together  in  a  round  bottom  ^  liter  flask  to  100° 
a  mixture  of  20  grams  of  phenol  and  20  grams  of  concen- 
trated sulphuric  acid  until  complete  solution  takes  place.1 
What  is  formed?  Remove  the  burner,  dilute  with  twice 
the  volume  of  water,  and  add  the  solution  (from  a  separa- 
tory  funnel  and  with  constant  shaking),  gradually  and 
carefully,  to  100  grams  of  cone,  nitric  acid.  Warm  the 
mixture  on  the  water  bath  until  the  red  color  changes  to 
yellow,  then  pour  into  a  liter  of  water,  filter  off  the  crystals 
on  a  Buchner  funnel,  drain  thoroughly,  wash  with  water, 
and  purify  by  recrystallization  from  hot  water  containing 
0.1%  sulphuric  acid. 

Determine  color,  odor,  taste  (poison),  crystal  form, 
melting  point  and  solubility  of  the  compound. 

Does  an  aqueous  solution  of  the  acid  dye  silk  or  wool 
permanently?  Save  specimens  of  the  dyed  cloth.  Satu- 
rate some  of  the  picric  acid  with  a  solution  of  sodium  car- 
bonate, and  add  to  the  hot  filtered  solution  a  few  crystals 
of  sodium  carbonate.  What  takes  place?  Explain.  Does 
phenol  react  with  a  solution  of  sodium  carbonate?  Does 
tne  dry  sodium  salt  or  the  acid  explode  when  heated  or 
struck  with  a  hammer?  Save  specimens  of  both  the  acid 
and  the  sodium  salt,  and  write  out  all  reactions. 

*A  sample  taken  out  of  the  mass  should  be  completely  soluble  in 
water. 


126 


EXPERIMENT  62 

BENZYL  ALCOHOL  AND  BENZOIC  ACID  FROM 
BENZALDEHYDE 

Shake  20  grams  of  benzaldehyde  in  a  cork  stoppered 
bottle  with  a  cold  solution  of  18  grams  of  potassium 
hydroxide  in  12  grams  of  water  until  a  permanent  emulsion 
is  formed  and  allow  the  mixture  to  stand  over  night.  Add 
water  until  the  pasty  mass  of  crystals  goes  into  solution 
and  extract  the  benzyl  alcohol  from  the  clear  solution  by 
shaking  several  times  with  ether.  Distil  off  the  ether, 
observing  the  usual  precautions,  and  then  distil  the  alcohol, 
noting  the  boiling  point.  Determine  its  color,  odor,  solu- 
bility and  taste.  Is  it  a  primary  alcohol?  Add  hydro- 
chloric acid  in  excess  to  the  alkaline  solution  and  recrys- 
tallize  the  precipitate  from  hot  water.  Compare  it  with 
the  benzoic  acid  obtained  in  Experiments  57  and  63.  How 
do  acetic  and  formic  aldehydes  react  when  treated  with 
alkalies?  Save  specimens  of  benzyl  alcohol  and  of  benzoic 
acid.  Use  the  rest  of  the  benzoic  acid  together  with  that 
obtained  in  Experiment  63  in  Experiment  64. 

Show  how  benzyl  benzoate  could  be  made  by  the 
Baumann-Schotten  reaction.  How  is  cinnamic  acid  made 
from  benzaldehyde  (Perkm's  synthesis)? 


128 


EXPERIMENT  63 
BENZOIC  ACID 

(Hood) 

Boil  10  grams  of  benzyl  chloride  (in  a  500  cc.  retort  with 
neck  directed  upwards),  with  a  mixture  of  30  grams  of 
cone,  nitric  acid  and  20  grams  of  water  until  completely 
oxidized  (about  ten  hours).  When  the  odor  of  benzyl 
chloride  has  disappeared,  and  no  oil  separates  out  on  cool- 
ing, let  the  contents  of  the  retort  cool,  and  filter  off  the 
crystals.  If  the  crystals  are  colored,  decolorize  them  by 
boiling  the  aqueous  solution  with  boneblack,  or  by  re- 
crystallization  from  boiling  dilute  nitric  acid.  What  is 
this  substance  thus  obtained?  By  what  other  methods 
have  you  already  prepared  it?  Determine  its  melting 
point,  odor,  taste,  crystal  form  and  solubility.  Is  it 
volatile  with  steam? 

Sublime  a  small  amount  of  the  benzoic  acid  as  follows: 
Put  a  little  into  the  bulb  of  a  straight  calcium  chloride 
tube,  heat  until  the  acid  melts  and  then  pass  a  slow  current 
of  air  through  the  tube.  The  length  of  the  tube  is  in- 
creased by  wrapping  a  piece  of  paper  around  it  and  fasten- 
ing it  with  a  rubber  band.  The  vapors  condense  on  the 
paper. 

Save  speciments  of  the  crystallized  and  the  sublimed 
benzoic  acid. 

How  is  benzoic  acid  made  on  the  arge  scale? 


130 


EXPERIMENT  64 
ETHYL  BENZOATE 

Dissolve  25  grams  of  benzole  acid  l  in  100  grams  of  ab- 
solute alcohol,  add  to  the  solution  5  grams  of  concentrated 
sulphuric  acid,  and  heat  the  mixture  to  boiling  in  a  flask 
connected  with  a  reflux  condenser  for  three  hours.  Pour 
the  contents  of  the  flask  into  five  times  its  volume  of  water, 
neutralize  the  acid  with  dry  sodium  carbonate,  separate 
the  oil  from  the  solution,  wash  with  water,  dry  with  po- 
tassium carbonate,  and  distil,  noting  the  boiling  point. 

Determine  color,  specific  gravity,  odor,  taste  and  solu- 
bility. What  is  formed  when  some  of  the  substance  is 
boiled  with  caustic  soda  solution?  Try  it.  Save  a  speci- 
men of  the  ester. 

1  Use  the  benzole  acid  made  in  Experiments  62  and  63. 


132 


EXPERIMENT  65 

GRIGNARD'S   REACTION 
BENZHYDROL 

(Diphenyl  Carbinol) 

2.4  grams  (1  mol.)  of  magnesium  turnings  and  a  small 
crystal  of  iodine  are  placed  in  a  dry  250  cc.  R.  B.  flask  and 
warmed  gently  over  a  free  flame  until  the  color  of  the 
iodine  vapor  becomes  visible  in  the  flask.  17.2  grams  (1.1 
mol.)  of  pure,  dry  bromobenzene  dissolved  in  50  cc.  of 
absolute  ether  (dried  over  sodium)  are  then  added  and  the 
flask  is  connected  with  a  reflux  condenser^  the  inner  tube 
of  which  must  be  dry  and  clean.  A  small  calcium  chloride 
tube  containing  calcium  chloride  and  soda-lime  is  fitted 
by  means  of  a  cork  to  the  upper  end  of  this  tube  in  order 
to  protect  the  contents  of  the  flask  from  the  carbon  dioxide 
and  moisture  of  the  air. 

The  flask  is  dipped  into  warm  water  (about  50°)  until 
the  reaction  starts  and  the  ether  begins  to  boil,  after  which 
it  is  removed,  as  the  heat  of  the  reaction  is  sufficient  to 
keep  the  ether  boiling.  When  the  ether  has  ceased  boil- 
ing, the  flask  is  heated  in  a  water  bath  to  the  boiling  point 
of  the  ether  until  all  of  the  magnesium  has  dissolved. 
What  substance  is  present  in  the  ether  solution?  If  a 
dark  colored  precipitate  forms  it  is  due  to  impurities  in 
the  magnesium.  The  flask  is  now  cooled  in  ice  water  and 
a  mixture  of  10.6  grams  (1  mol.)  of  freshly  distilled  pure 
benzaldehyde  and  50  cc.  of  absolute  ether  is  added  slowly, 
drop  by  drop,  from  a  separatory  funnel  inserted  in  the 
inner  tube  of  the  condenser  in  place  of  the  cork  and  the 
calcium  chloride  tube.  The  flask  is  gently  shaken  after 
the  addition  of  each  drop  of  the  solution  of  the  benzalde- 
hyde and  no  more  of  the  solution  is  added  until  the  first 
violent  reaction  is  over.  Care  must  also  be  taken  to  keep 
134 


the  flask  surrounded  with  ice  water  to  prevent  the  ether 
from  boiling  too  violently. 

When  all  of  the  benzaldehyde  has  been  added  and  the 
reaction  is  complete,  the  contents  of  the  flask  are  poured 
into  a  porcelain  dish  containing  100  grams  of  crushed  ice 
and  5  cc.  of  glacial  acetic  acid;  observing  the  usual  pre- 
cautions when  working  with  ether  solutions.  After  the 
ice  has  melted  pour  the  contents  of  the  dish  into  a  1  liter 
R.  B.  flask  and  subject  them  to  steam  distillation  in  order 
to  remove  the  ether  and  any  unchanged  benzaldehyde  and 
bromobenzene,  observing  the  usual  precautions  when  dis- 
tilling ether.  On  cooling  the  flask  the  oily  layer  will 
solidify.  The  solid  is  filtered  off  on  a  Buchner  funnel  and 
dried  in  the  air  on  drying  paper.  It  is  purified  by  re- 
crystallization  from  ligroin.  Determine  the  melting  point, 
odor,  color,  crystal  form  and  solubility  of  the  substance. 
What  does  this  product  give  on  oxidation  and  what  does 
this  show  regarding  the  structure  of  the  compound?  How 
is  benzyl  alcohol  (phenyl  carbinol)  made  from  benzalde- 
hyde? Save  a  specimen  of  benzhydrol. 


136 


EXPERIMENT  66 
PHTHALIC   ANHYDRIDE   AND   PHTHALIC  ACID 

(Hood), 

Grind  together  in  a  mortar  until  thoroughly  mixed  50 
grams  of  naphthalene  and  13  grams  of  mercuric  sulphate 
(or  mercuric  oxide).  Put  this  mixture  in  a  1  liter  tubu- 
lated retort  and  add  375  grams  of  cone,  sulphuric  acid. 
Clamp  the  retort  with  the  neck  turned  upward  and  heat 
gently1  over  a  wire  gauze  until  all  the  naphthalene  has 
dissolved  (about  30  minutes).  Explain.  Turn  the  neck 
of  the  retort  down  and  insert  it  tightly  into  the  neck  of 
a  tubulated  retort  receiver.  The  opening  (tubulure)  of 
this  receiver  is  connected  with  a  cork  and  glass  tubing 
which  should  extend  to  the  hood  exhaust,  and  the  receiver 
is  surrounded  with  cracked  ice.  The  retort  is  then  gently 
heated  with  a  small  moving  luminous  flame  and  the  heat 
is  gradually  increased  as  needles  of  the  anhydride  appear 
in  the  neck  of  the  retort  and  the  sulphuric  acid  distils. 
Continue  heating  until  as  much  as  possible  of  the  liquid 
has  been  distilled  over  (1^-2  hours)  What  gases  are 
given  off?  Why  was  mercuric  sulphate  (or  oxide)  used? 
Remove  the  substance  from  the  neck  of  the  retort  and 
add  it  together  with  the  mixture  in  the  receiver  to  a  porce- 
lain dish  containing  300  grams  of  cracked  ice  with  stirring. 
Filter  off  the  anhydride  on  a  Buchner  funnel,  wash  it  with 
ice  water  until  free  from  sulphuric  acid  and  dry  in  the  air 
on  drying  paper.  The  solid  is  then  resublimed  as  follows : 
It  is  placed  in  a  watch  glass  which  rests  on  the  edge  of  a 
circular  opening  (1  in.  diam.)  in  an  asbestos  board  which 
in  turn  is  placed  over  a  piece  of  wire  gauze.  A  filter  paper, 
punctured  with  small  holes  with  the  small  blade  of  a  pen- 
knife is  placed  over  the  watch  glass  and  fitted  tightly 
around  the  edge.  A  beaker  is  inverted  over  the  watch 

1  Exercise  great  care  hi  working  with  hot  cone,  sulphuric  acid. 
138 


glass.  The  watch  glass  is  then  heated  very  gently,  using  a 
small  flame.  Needles  form  above  the  filter  paper.  Should 
these  begin  to  melt  decrease  the  heat.  Save  a  specimen 
of  the  sublimed  material.  Determine  its  melting  point 
and  solubility.  How  could  you  test  for  phthalic  anhydride? 
(See  Fluorescein.) 

Dissolve  about  a  gram  of  the  anhydride  by  boiling  it 
with  a  small  amount  of  water  in  a  250  cc.  Erlenmeyer  flask, 
using  an  ebulator  tube  and  filter  the  solution  if  necessary. 
What  is  present  in  this  solution?  Let  stand  over  night. 
If  no  crystals  appear,  concentrate  the  so  ution.  Filter 
off  the  crystals  and  determine  the  melting  po  nt,  crystal 
form,  color,  taste  and  solubility.  Is  the  substance  an 
acid?  What  does  phthalic  anhydride  give  when  heated 
with  alcohol?  Save  a  specimen  of  phthalic  acid. 


EXPERIMENT  67 
SALICYLIC  ACID 

Boil  10  cc.  of  oil  of  wintergreen  with  100  cc.  of  a  20% 
solution  of  sodium  hydroxide  in  a  round  bottom  flask 
connected  with  a  reflux  condenser  until  it  has  all  disap- 
peared. What  is  formed?  When  cool,  acidify  with 
hydrochloric  acid  Filter  off  the  precipitated  substance, 
recrystallize  it  from  hot  water  and  determine  its  melting 
point,  color,  crystal  form,  solubility  and  taste.  What 
change  takes  place  when  some  of  the  substance  is  care- 
fully heated  in  a  dry  test  tube?  What  are  the  products? 
Dissolve  some  of  the  acid  in  water,  and  add  a  few  drops 
of  a  solution  of  ferric  chloride.  What  takes  place?  Add 
a  few  drops  of  bromine  water  to  an  aqueous  solution  of 
salicylic  acid  and  note  what  takes  place.  Explain.  Save 
a  specimen  of  the  acid. 

For  what  purposes  is  salicylic  acid  used? 


140 


EXPERIMENT  68 

ACETYL  SALICYLIC  ACID 

(Aspirin) 

Heat  5  grams  of  salicylic  acid  with  8  grams  of  acetic 
anhydride  and  1  cc.  of  concentrated  sulphuric  acid  in  a 
small  flask  in  a  water  bath  raising  the  temperature  gradu- 
ally to  90°  or  until  all  the  salicylic  acid  goes  into  solution. 
Pour  the  solution  while  hot  into  100  cc.  of  cold  water  con- 
taining 100  grams  of  cracked  ice.  What  is  the  precipitate? 
Filter  off  the  precipitate  on  a  Buchner  funnel,  wash  with 
ice  water  and  dry  in  the  air  on  drying  paper.  Recrystallize 
from  benzene  and  determine  its  melting  point,  solubility, 
color,  crystal  form  and  taste.  Treat  0.1  gram  of  the  sub- 
stance with  5  cc.  of  alcohol  and  dilute  with  20  cc.  of  water. 
Add  to  the  mixture  a  drop  of  ferric  chloride  solution.  Is 
there  any  color  formed?  Explain.  (See  Salicylic  acid.) 
What  does  it  give  when  boiled  for  some  time  with  water? 
Test  the  boiled  solution  with  a  drop  of  ferric  chloride  so- 
lution. Is  aspirin  an  acid?  Shake  some  of  the  aspirin 
with  water  and  a  little  calcium  carbonate.  Filter  and  test 
the  filtrate  for  calcium  with  an  ammonium  oxalate  solution. 
Explain.  Save  a  specimen  of  the  crystallized  aspirin.  For 
what  purpose  is  it  used? 


142 


EXPERIMENT  69 

SALICYLIC  AND  PARAHYDROXY  BENZOIC  ALDE- 
HYDES 

Dissolve  160  grams  of  sodium  hydroxide  by  heating 
with  160  cc.  of  water  in  a  liter  round  bottom  flask  and  add 
50  grams  of  phenol.  Cool  the  contents  of  the  flask  to 
60°-65°  by  immersing  in  cold  water  and  connect  the  flask 
with  a  reflux  condenser  and  a  thermometer,  the  bulb  of 
which  dips  below  the  surface  of  the  liquid.  Add  40  grams 
of  chloroform  gradually  (5  cc.  at  a  time)  through  the  inner 
tube  of  the  condenser  and  shake  the  flask  gently.  The 
liquid  becomes  red  and  the  temperature  rises.  When  it 
reaches  70°,  cool  the  flask  in  water  till  the  thermometer 
indicates  65°.  During  the  entire  reaction  the  tempera- 
ture should  be  kept  between  65°-70°.  After  waiting  10 
to  15  minutes  add  40  grams  more  of  chloroform  in  the 
same  manner  as  described  above.  Finally  after  about 
half  an  hour  add  40  grams  more  of  chloroform,,  taking  care 
to  keep  the  temperature  between  65°-70°  by  heating  in  a 
water  bath.  Frequent  shaking  of  the  mixture  is  essential 
for  the  success  of  the  experiment.  When  the  reaction  is 
complete  (about  2  hours)  distil  off  the  unused  chloroform 
with  steam.  The  red  alkaline  fluid  in  the  flask  is  then 
allowed  to  cool  and  acidified  carefully  with  dilute  sulphuric 
acid  when  it  becomes  nearly  colorless.  Then  distil  with 
steam  until  oily  drops  no  longer  distil  with  the  water. 
Save  the  contents  of  the  flask  from  which  the  oil  was  dis- 
tilled. Extract  the  aqueous  distillate  with  ether,  separate 
it  from  the  water  and  distil  off  the  ether,  observing  the  usual 
precautions.  The  oil  which  remains  is  a  mixture  of  un- 
changed phenol  and  salicylic  aldehyde.  The  salicylic 
aldehyde  is  separated  from  the  phenol  by  treating  the 
mixture  with  twice  its  volume  of  a  concentrated  solution 
144 


of  sodium  bisulphite  (made  by  dissolving  56  grams  of 
powdered  sodium  acid  sulphite  in  100  cc.  of  water  at  room 
temperature).  On  stirring  with  a  glass  rod  the  sodium 
bisulphite  compound  of  the  salicylic  aldehyde  crystallizes 
out.  After  standing  for  some  time  the  crystals  are  filtered 
off  on  a  Buchner  funnel  and  washed  several  times  with 
alcohol  and  then  with  ether  to  remove  the  phenol.  The 
crystals  are  then  decomposed  by  warming  on  the  water 
bath  with  dilute  sulphuric  acid.  When  cold,  extract  the 
salicylic  aldehyde  with  ether,  separate  the  ether  extract 
from  the  dilute  sulphuric  acid,  dehydrate  it  with  anhydrous 
sodium  sulphate  and  distil  off  the  ether  with  the  usual 
precautions.  The  aldehyde  is  then  distilled,  noting  the 
boiling  point.  Determine  odor,  color,  specific  gravity  and 
solubility  of  the  substance  and  save  specimens  of  it  and 
its  bisulphite  compound. 

Filter  the  contents  of  the  flask  from  which  the  oil  was 
distilled  (see  above)  through  a  wet  filter  and  saturate  the 
clear  nitrate  with  salt.  Filter  off  the  p-hydroxy  benzoic 
aldehyde  and  extract  the  filtrate  with  ether.  Evaporate 
the  ether  and  crystallize  the  combined  quantity  of  the 
aldehyde  from  water  after  adding  sulphur  dioxide.  De- 
termine the  melting  point,  color,  crystal  form  and  solu- 
bility of  the  p-hydroxy  benzaldehyde  and  save  a  specimen 
of  the  substance.  Does  its  aqueous  solution  give  any 
color  with  ferric  chloride  solution?  Does  the  aqueous 
solution  of  salicylic  aldehyde  give  any  color  with  this 


146 


EXPERIMENT  70 
PARAROSANILINE 

Heat  1  gram  of  a  mixture  of  freshly  distilled  aniline  and 
paratoluidine  (2  molecules  of  aniline  and  1  of  paratoluidine) 
in  a  small  flask  with  3  grams  of  powdered  mercuric  chlo- 
ride and  2  grams  of  freshly  distilled  aniline  in  a  bath  of 
Crisco  or  cone,  sulphuric  acid  (hood)  to  180°-200°  for  1^ 
to  2  hours.  Take  the  temperature  by  means  of  a  ther- 
mometer dipping  into  the  fluid  in  the  flask  and  use  the  ther- 
mometer to  stir  the  mixture.  What  is  formed?  Extract 
the  mixture  in  the  flask  several  times  with  alcohol,  filter 
and  evaporate  the  filtrate  to  dryness  on  a  water  bath. 
Does  an  aqueous  solution  of  the  substance  dye  wool,  silk 
or  cotton?  Save  a  specimen  of  the  colored  aqueous  solu- 
tion and  specimens  of  the  dyed  cloth. 


148 


EXPERIMENT  71 
FLUORESCEIN 

Grind  together  in  a  mortar  15  grams  of  phthalic  an- 
hydride and  22  grams  of  resorcinol  and  heat  the  mixture 
in  a  nickel  crucible  in  a  Crisco  bath  to  180°.  Then  add  7 
grams  of  powdered  fused  zinc  chloride  slowly  and  stir  the 
mixture  with  a  glass  rod.  Increase  the  temperature  to 
210°  and  continue  the  heating  at  this  temperature  until 
the  fused  mass  solidifies. 

Cool  the  crucible,  remove  the  fused  mass  by  mechanical 
means,  dissolve  it  in  dilute  caustic  soda  solution,  filter  and 
precipitate  the  fluorescein  from  the  boiling  solution  with 
cone,  hydrochloric  acid.  Filter  off  the  precipitate  on  a 
Buchner  funnel  and  dry  at  80°.  Does  the  alkaline  solu- 
tion fluoresce?  Dilute  and  note  the  dilution  at  which  the 
solution  becomes  colorless.  Heat  2  grams  of  the  fluores- 
cein with  acetic  anhydride  until  it  all  goes  into  solution. 
Cool  and  pour  into  water.  Filter  off  the  diacetate  after 
it  solidifies  and  recrystallize  it  from  alcohol.  Determine 
its  melting  point.  Note  that  while  fluorescein  is  colored 
the  diacetate  is  colorless.  Explain.  Save  a  specimen  of 
the  fluorescein  and  of  the  diacetate.  Use  the  rest  of  the 
fluorescein  in  Experiment  72. 


150 


EXPERIMENT  72 
EOSIN  AND   SOLUBLE  EOSIN 

Put  15  grams  of  fluorescein  and  60  grams  of  alcohol 
into  a  250  cc.  Erlenmeyer  flask.  Drop  in  slowly,  from  a 
small  separatory  funnel,  33  grams  (11  cc.)  of  bromine, 
shaking  the  mixture  hi  the  flask.  When  about  half  the 
bromine  has  been  added  a  clear,  dark-red  solution  results. 
What  is  present  in  this  solution?  On  further  addition  of 
bromine  brick-red  leaflets  separate.  What  is  this  product? 
After  standing  for  2  hours  the  crystals  are  filtered  off, 
washed  with  alcohol  and  dried  in  the  air  on  drying  paper. 
Heat  a  small  portion  of  the  crystallized  eosin  in  a  porcelain 
dish  to  110°  in  an  air  bath  and  note  any  change  of  color. 
Save  a  specimen  of  the  crystallized  eosin  and  convert  the 
rest  into  the  sodium  salt  (soluble  eosin).  For  this  purpose 
grind  6  grams  of  eosin  with  1  gram  of  anhydrous  sodium 
carbonate  in  a  mortar.  Place  the  ground  mixture  in  a 
200  cc.  beaker  and  moisten  it  with  a  little  alcohol.  Add 
5  cc.  of  water  and  heat  on  the  water  bath  until  the  evolu- 
tion of  carbon  dioxide  ceases.  Then  add  20  grams  of 
alcohol,  heat  to  boiling  and  filter  the  hot  solution.  On 
standing  the  soluble  sodium  salt  crystallizes.  Save  a 
specimen  of  the  soluble  eosin. 


152 


EXPERIMENT  73 
CRYSTAL  VIOLET 

Mix  5  grams  of  dimethylaniline,  2  grams  of  Michler's 
Ketone  (tetramethyldiamino  benzophenone)  and  2  grams 
of  phosphorus  oxy chloride  in  a  1  liter  R.  B.  flask.  Heat 
the  flask  (Hood)  for  5  hours  in  an  actively  boiling  water 
bath.  Then  add  300  cc.  of  water  and  a  solution  of  caustic 
soda  until  the  mixture  is  distinctly  alkaline  and  subject  it 
to  steam  distillation  to  remove  any  unchanged  dimethyl- 
aniline  (test  some  of  the  last  aqueous  distillate  with 
bromine  water  and  some  of  the  first  aqueous  distillate  with 
the  same  reagent).  Cool  and  filter  off  the  color  base 
(carbinol)  on  a  Buchner  funnel,  wash  it  with  water,  put 
it  in  a  500  cc.  flask  and  then  bo  1  it  with  200  cc.  portions 
of  a  mixture  of  1  liter  of  water  and  5  grams  of  cone,  hydro- 
chloric acid.  Filter  the  hot  solutions  from  the  undis- 
solved  color  base  and  continue  the  extraction  until  almost 
all  of^he  substance  has  been  dissolved.  Cool  the  com- 
bined filtrates  and  add  pulverized  salt  as  long  as  it  dissolves 
freely,  stirring  the  solution  constantly  during  the  addition. 
Is  the  d|:e  precipitated?  What  is  this  process  called? 
Filter  off  the  dye  on  a  Buchner  funnel  and  recrystallize  it 
from  a  small  amount  of  hot  water.  Is  the  dye  soluble  in 
water?  Does  the  aqueous  solution  give  a  precipitate  with  •* 
a  solution  of  caustic  soda?  Is  the  color  base  of  crystal 
violet  colored?  What  takes  place  when  this  color  base 
dissolves  hi  dilute  hydrochloric  acid?  Does  crystal 
violet  dye  wool,  silk  or  cotton?  Save  specimens  of  crystal 
violet  and  of  the  dyed  cloth. 


154 


EXPERIMENT  74 
INDIGO  CARMINE  > 

Dissolve  one  gram  of  indigocarmine  in  250  cc.  of  water 
contained  in  a  500  cc.  Erlenmeyer  flask  and  add  to  this 
solution  one  gram  of  sodium  hydrosulphite.  Shake  the 
mixture  thoroughly  until  the  indigocarmine  is  completely 
reduced  and  a  yellow  solution  results.  What  is  indigo- 
carmine? What  is  sodium  hydrosulphite?  What  is 
formed  on  the  reduction  of  indigocarmine?  Explain. 

Saturate  some  pieces  of  cheese  cloth  with  the  yellow 
solution,  dry  in  the  air  and  wash  with  water.  Is  the  cloth 
permanently  dyed?  Explain. 

Expose  some  of  the  yellow  solution  to  the  air  or  blow 
air  through  some  of  it  and  note  what  happens.  Explain. 

Does  a  solution  of  indigocarmine  dye  wool  and  silk? 

Save  a  specimen  of  the  dyed  cloth. 

1See  Cain  and  Thorpe,  Synthetic  Dyestuffs. 


156 


EXPERIMENT  75 
BENZIDINE   FROM   NITROBENZENE 

Eight  grams  of  sodium  hydroxide  are  dissolved  by  heat- 
ing with  5  to  10  cc.  of  water  in  a  250  cc.  Erlenmeyer  flask 
and  50  cc.  of  alcohol  are  added.  Add  4  cc.  of  nitrobenzene, 
warm  gently  on  an  asbestos  board  with  a  circular  opening 
}/£  inch  in  diameter  placed  over  a  piece  of  wire  gauze  and 
add  slowly  10  grams  of  zinc  dust  in  small  portions,  waiting 
for  any  action  to  cease  before  a  new  portion  is  added. 
Note  the  color  change.  When  all  the  zinc  dust  has  been 
added,  connect  the  flask  with  a  cork  and  reflux  condenser 
and  boil  the  contents  until  no  red  oil  is  formed  when  a 
little  of  the  solution  is  poured  into  10  cc.  of  dilute  sulphuric 
acid  contained  in  a  test  tube.  The  rea'ction  is  then  com- 
plete. The  solution  is  poured  into  an  excess  of  dilute 
sulphuric  acid  and  heated  to  boiling.  What  is  the  pre- 
cipitate formed?  Cool  and  filter  off  the  precipitate  on  a 
Buchner  funnel,  wash  with  water  and  recrystallize  some 
of  the  product  from  boiling  water.  Is  it  very  soluble  in 
water? 

Boil  the  rest  of  the  salt  with  an  excess  of  a  solution  of 
caustic  soda,  filter  the  solution  while  hot  and  let  stand 
till  cold.  What  is  the  product  which  crystallizes  out? 
Filter,  wash  with  water  ^d  recrystallize  the  product 
from  boiling  water.  Filter  off  the  recrystallized  product, 
wash  with  water  and  dry  in  the  air  on  drying  paper. 
Determine  its  melting  point  and  solubility.  Dissolve  a 
small  amount  of  the  benzidine  in  boiling  water  in  a  test 
tube  and  add  a  solution  of  potassium  bichromate.  Note 
what  takes  place.  Is  this  reaction  characteristic  of  ben- 
zidine? Save  specimens  of  the  crystallized  sulphate  and 
of  the  crystallized  benzidine.  How  is  benzidine  con- 
verted into  diphenyl?  For  what  purpose  is  benzidine 
used  commercially? 

158 


EXPERIMENT  76 
ORANGE  II 

Dissolve  5  grams  of  crystallized  sulphanilic  acid  in 
dilute  caustic  soda  solution,  adding  the  caustic  soda  solu- 
tion carefully  and  taking  care  not  to  have  an  excess  present. 
The  volume  of  the  liquid  should  be  about  200  cc.  Ice  is 
added  and  the  mixture  is  stirred  until  the  temperature  is 
about  5°.  Add  10  cc.  of  cone,  hydrochloric  acid  and  then 
slowly  through  a  separatory  funnel  a  solution  of  2.5  grams 
of  sodium  nitrite  in  25  cc.  of  water,  testing  from  time  to 
time  a  drop  of  the  solution  with  starch-iodide  paper  to  see 
when  an  excess  of  nitrous  acid  is  present  and  keeping  the 
temperature  about  5°  by  stirring.  What  compound 
crystallizes  out? 

Dissolve  3  grams  of  /3-naphthol  in  a  solution  of  1  gram 
of  caustic  soda  dissolved  in  10  cc.  of  water,  dilute  with 
50  cc.  of  water  and  cool  to  15°.  Add  the  suspension  of 
the  diazonium  salt  gradually,  stirring  the  solution  and 
keeping  the  temperature  at  about  15°.  When  all  the 
diazonium  salt  has  been  added  the  mixture  should  have  a 
slight  alkaline  reaction1  and  should  be  allowed  to  stand 
for  an  hour.  Add  some  saturated  salt  solution  to  precipitate 
the  rest  of  the  dye,  filter  off  the  precipitate  on  a  Buchner 
funnel,  and  dry  at  80°.  Is  the  dye  soluble  in  water?  Does 
its  solution  give  a  colored  precipitate  with  hydrochloric 
acid?  Explain.  Does  it  dye  wool  and  silk  from  an  acid 
bath?  Save  specimens  of  the  dye  and  of  the  dyed  cloth. 

1  Test  with  brilliant  yellow  paper.  If  it  is  not  alkaline,  make  it 
alkaline. 


160 


EXPERIMENT  77 

ANTHRAQUINONE 

(Hood) 

Cover  5  grams  of  anthracene  with  six  to  eight  times  its 
weight  of  alcohol  (so  that  on  boiling  the  alcohol  only  part 
of  the  anthracene  dissolves),  then  pass  a  strong  current 
of  chlorine1  into  the  boiling  liquid.  After  some  time  a 
solution  is  obtained,  which  on  further  addition  of  chlorine 
gives  a  precipitate  (?).  After  cooling,  filter,  wash  the 
precipitate  with  cold  alcohol,  then  with  dilute  caustic 
soda  solution,  and  finally  with  water,  dry,  and  sublime. 

Determine  color,  crystal  form,  melting  point  and  solu- 
bility of  the  substance.  Warm  one  part  of  the  sub- 
stance with  zinc  dust  (2  parts)  and  caustic  soda  solution. 
(30  parts  of  50%  solution).  What  takes  place?  Explain. 
Save  a  specimen  of  the  anthraquinone.  How  is  anthra- 
quinone  made  technically? 

1  Use  a  wide  delivery  tube.     Wear  goggles. 


162 


EXPERIMENT  78 

ALIZARIN 

(Hood) 

Heat  20  grams  of  anthraquinone  in  a  ^  liter  long  neck 
flask  with  25  grams  of  fuming  sulphuric  acid  (45  to  50% 
SOs)  gradually  in  a  Crisco  bath  to  160°  for  one  hour.  What 
is  formed?  Pour  the  mixture  cautiously  into  2  liters  of 
hot  water  contained  in  a  porcelain  dish,  stirring  the  water 
vigorously.  Boil  for  a  few  minutes  and  filter  the  solution 
to  remove  any  unchanged  anthraquinone.1  Warm  the 
filtrate  and  add  solid  sodium  carbonate  gradually  with 
stirring  until  the  solution  has  a  neutral  reaction.  If  on 
cooling  the  sodium  salt  does  not  crystallize  out,  concen- 
trate the  solution.  Filter  off  the  sodium  salt.  Save  a 
specimen  of  the  crystallized  "silver  salt"  and  convert  the 
rest  into  alizarin.  For  this  purpose  dissolve  one  part  of 
the  "silver  salt"  in  as  small  a  quantity  of  hot  water  as 
possible  in  an  autoclave,  add  5  parts  of  solid  caustic  soda 
and  0.2  parts  of  potassium  chlorate.  Close  the  autoclave 
and  heat  the  mixture  for  20  hours  at  170°.  Cool  and 
remove  the  melted  mass  by  boiling  with  water  and  by  me- 
chanical means.  Saturate  the  boiling  solution  in  a  porce- 
lain dish  with  concentrated  hydrochloric  acid,  boil  for 
fifteen  minutes,  filter  off  the  precipitate  on  a  Buchner 
funnel  while  hot  and  wash  it  with  hot  water  until  the  hydro- 
chloric acid  is  removed.  Dry  and  sublime.  What  is  this 
substance?  Determine  its  color,  melting  point,  crystal 
form  and  solubility.  Does  it  dissolve  with  color  in  alka- 
lies? Explain.  Does  it  dye  cotton?  What  colors  does 
it  give  with  the  different  mordants?  What  is  formed  by 
heating  some  with  ten  times  its  weight  of  zinc  dust  in  a 
test  tube?  Save  a  specimen  of  the  alizarin. 

1  The  anthraquinone  recovered  should  be  washed  with  water  till 
free  from  acid,  dried  in  the  air  on  drying  paper  and  put  in  the  bottle 
labeled  "Recovered  Anthraquinone." 
164 


Abfflte 


JNDEX 


te  alcohol,  28 

Acetanilide,  108 

Acetic  acid,  46 

Acetic  acid,  detection,  46 

Acetic  aldehyde,  36,  66 

Acetic  anhydride,  52 

Acetic  ether,  54 

Acetic  ether,  saponification,  56 

Acetyl  chloride,  50 

Acetylene,  94 

Acetyl  salicylic  acid,  142 

Acrolein,  92 

Alcohol,  absolute,  28 

Aldehyde,  36,  66 

Aldehyde  ammonia,  38 

Aldehyde,  detection,  40 

Alizarin,  164 

Allyl  alcohol,  92 

Aluminum,  separation  from  man- 
ganese, etc.,  48 

Amine,  primary,  detection,  104 

Ammonium  cyanate,  urea  from, 
88 

Ammonium  thiocyanate,  66 

Aniline,  102 

Aniline,  phenol  from,  122 

Aniline,  detection,  104 

Anthraquinone,  162 

Asperin,  142 

Benzaldehyde,    benzyl    alcohol 

and  benzoic  acid  from,  128 
Benzene,  96 

Benzene  diazonium  chloride,  108 
Benzene  sulphonamide,  116 
Benzene  sulphonic  acjd,  114 
Benzene  sulphonyl  chloride,  116 
Benzhydrol,  134 
Benzidine,  158 
Benzoic  acid,  118,  128,  130 


Benzoic  acid,  benzene  from,  96 

Benzonitrile,  118 

Benzyl  alcohol,  128 

Benzyl  chloride,  130 

Boiling  point  determination,  10 

Calcium  carbide,  94 
Calcium  ethyl  sulphate,  30 
Cane  sugar,  hydrolysis,  78 
Carbamine,  phenol,  104 
Carbolic  acid,  120,  122 
Cellulose,  78 
Cellulose  acetate,  80 
Chloroform,  16 
Crystal  violet,  154 
Cyanate,  potassium,  62 
Cyanbenzene,  118 
Cyanide,  potassium,  58 

Diazonium  compounds,  108 
Diethyl  oxalate,  86 
Dinitrobenzene,  100 
Diphenyl  carbinol,  134 
Distillation,  fractional,  1,  6 

Eosin,  152 

Ether,  32 

Ether,  acetic,  54 

Ethyl  acetate,  54 

Ethyl    acetate,    saponification, 

56 

Ethyl  aldehyde,  36,  66 
Ethyl  benzoate,  132 
Ethyl  bromide,  22 
Ethylene  and  ethylene  bromide, 

90 

Ethyl  ether,  32 
Ethyl  formate,  86 
Ethyl  sulphuric  acid,  30 


167 


Fats,  saponification,  68 
Fehling's  solution,  74 
Fermentation  of  glucose,  24 
Ferric  s^Bfcj^basic,  74 
Ferricya^B^J^^sium,  60 
Fluorescein,  15<HP 
Formic  acid,  42 
Fractional  distillation,  1,  6 

Glucose,  fermentation,  24 
Glucose,  reducing  action,  74 
Glycerol,  68 
Grignard's  reaction,  134 

Hempel  distilling  tube,  6 
Hydrolysis  of  sucrose,  78 
Hydroxy  benzoic  aldehyde,  para, 
144 

Indigocarmine,  156 
Iodine,  detection,  84 
lodobenzene,  112 
lodobenzene  dichloride,  112 
lodoform,  20 
lodosobenzene,  112 
Iron,    separation   from   manga- 
nese, etc.,  48 
Isocyanide,  phenyl,  104 

Marsh  gas,  12 

Melting  point  determination,  8 
Metaldehyde  and  paraldehy  de,  38 
Methane,  12 

Naphthalene,    oxididatjon     to 

phthalic  acid,  138 
Nitroaniline,  meta,  106 
Nitrobenzene,  98 
Nitrophenols,  ortho-  and  para-, 

124 

Oil  of  wintergreen,   saponifica- 
tion, 140 
Orange  II,  160 
Ortho-nitrophenol,  124 
Oxalic  acid,  72 
Oxamide,  86 
Oxybenzene  aldehydes,  144 


itic  acid,  68 
•ahydroxy  benzoic  aldeh^le, 

144 
Paraldehyde  and  Metaldehyde, 

38 

Parlhitrophenol,  124 
Pararosaniline,  148 
Paroxybenzoic  aldehyde,  144 
Pasteur  salts,  24 
Phenol,  120,  122 
Phenol  from  aniline,  122 
Phenyl  cyanide,  118 
Phenyl  glucosazone,  76 
Phenyl  iodide,  112 
Phenyl  isocyanide,  104 
Phthalic  acid,  138 
Phthalic  anhydride,  138 
Picric  acid,  126 
Potassium  cyanate,  62 
Potassium  cyanide,  58 
Potassium  ferricyanide,  60 
Potassium  thiocyanate,  64 

Sacchorose,  hydrolysis,  78 

Salicylic  acid,  140 

Salicylic  aldehyde,  144 

Saponification,  56,  68 

Schweizer's  reagent,  82 

Silver  carbide,  94 

Silver  salt,  164 

Soap,  68 

Sodium  benzene  sulphonate,  114 

Soluble  eosin,  152 

Starch,  84 

Starch,  detection,  84 

Starch,  hydrolysis,  84 

Stearic  acid,  68 

Sucrose,  hydrolysis,  78 

Sulphuric  ether,  32 

Thiocyanate,  ammonium,  66 
Thiocyanate,  potassium,  64 
Trinitrophenol,  126 

Urea,  88 

Willesden  waterproofing,  82 


168 


7  3 


1  0 


UNIVERSITY  OF  CALIFORNIA  AT  LOS  ANGELES 

THE  UNIVERSITY  LIBRARY 
This  book  is  DUE  on  the  last  date  stamped  below 


APR  23  I94f 


OCT  2  5  1951  , 


DEC  4    195C 


WSCHARGE-URI 
«1 

JUN  2 11978 


NOV17 
NOV  15 19871 

Form  L-9-20m-8,'37 


APR27  »BD 
JUL17  *» 


